"I believe," Christopher (Huck) Look Jr. once said, "that I know the difference between a big black car and a little white car."

The laconic observation goes to the heart of one of the biggest controversies surrounding the accident at Chappaquiddick Island 10 years ago, when Sen. Edward M. Kennedy's black 1967 Oldsmobile plunged off a narrow bridge into the dark waters of a tideswept pond.

The dispute can be stated simply: If Look saw what he said he saw the night of the accident, Kennedy's account of the tragedy is a tissue of lies.

When the senator's car was pulled out of Poucha Pond on the morning of July 19, 1969. Look, then 41, was one of the onlookers. An Edgartown fuel-oil dealer and Dukes County deputy sheriff, he had a summer home on Chappaquiddick, and he had gone to Dike Bridge to help the police control traffic.

First, Mary Jo Kopechne's body was removed from the submerged sedan, which Edgartown police chief Dommick J. Arena, who was at the scene, already had identified as Kennedy's. Then, as the car, with its Massachusetts license plate, £78-207, came out of the water, Look walked over to Edgartown police officer Robert Brougier.

"Gee," Look told him, "that is the ssame car saw last night."

Chief Arena, at that point, was in a hurry to get back to the police station in Edgartown. He said in an interview this month that he shrugged off the additional information that Brougier passed on to him at the scene.

"I thought, 'What the hell does that mean to me?'" he recalls. Later that weekend Arena found out. reporter told the chief that Look was convinced he had seen the car long after Kennedy said he drove it off the bridge.

Kennedy said the accident happened shortly after 11:15 p.m. on Friday, July 18, when he and Kopechne left their friends at a rented cottage on the island where they had gathered for a party and cookout.

Look told Arena he had seen a dark sedan with a Massachusetts license plate, beginning with the letter "L," around 12:45 a.m. July 19, more than an hour later. He said he spotted it on the way home from work at the T-shaped intersection of Chappaquiddick's only paved road and a dirt road leading to Dike Bridge. To others, Look said at the time that he also remembers two "7's" in the license plate -- the digits sticking in his mind because he had that number as a high school athlete.

The time element is crucial. If Look is right, Kennedy not only lied about when the accident happened, but it would seem, he was also with Kopechne somewhere on Chappaquiddick for more than an hour before the car plunged off the bridge. And if Look is right, Kennedy could not have done all he said he did after the accident -- including the second rescue effort with Joe Gargan and Paul Markham -- and gotten back to the hotel by 2:25 a.m.

(Gargan, a cousin of the senator, is a Boston lawyer; Markham is a former U.S. attorney and longtime Kennedy family friend.)

According to Arena's notes, Look said he saw "a man driving . . . someone next to him" and possibly "someone else in the back seat" although he wasn't sure of that. It could have been a purse that had been left in the Olds earlier by another woman at the party, Rosemary Keough. Look, who was wearing his deputy's uniform, said he got out of his car to ask if they needed directions, but as he approached the other car, it drove off down the dirt road toward Dike Bridge.

The senator has insisted that Look was mistaken, that the deputy might have seen the rented white Valiant that Kennedy, Markham and Gargan took to Dike Bridge after the accident in hopes of rescuing Kopechne. Look has put the issue more bluntly. "Either he's lying or I am," he once said. (The license plate of the Valiant was Y98-746.)

Kennedy also has testified that he, Markham and Gargan arrived at the bridge for the second rescue effort at 12:20 a.m. He said he knew the time because "I believe that I looked at the Valiant's clock and believe that it was 12:20."

The Valiant had no clock. Kennedy now says he thinks he looked at Markham's watch. (Neither Gargan nor Kennedy was wearing a watch.) "I mean, I would imagine his [Markham's] arm was up on the back seat," Kennedy told The Washington Post in an interview this month. But he still admits to no doubts that it was 12:20 a.m. "I was very conscious of time at the moment," he told CBS in another interview. "Because I knew time was ticking by."

At that moment, Look was still at the Edgartown Yacht Club, winding up a nighttime stint as a guard during the weekend festivities surrounding a boating race in which Kennedy had competed earlier in the day. Others at the Yacht Club confirmed that Look left around 12:25 a.m. in a Yacht Club launch that brought him to Chappaquiddick.

In his testimony at the inquest 5 1/2 months later, Look grew more precise about the license plate, saying "it began with an L and it had a 7 at the beginning and a 7 at the end." But if that was embellishment, there was other testimony that represented a complete turnabout from earlier statements.

One of the women at the party, Esther Newberg, told reporters again and again in a series of interviews she gave the week after the accident that she didn't see Kennedy or Kopechne leave and that no one was keeping track of the time. She said she had a "Mickey Mouse watch" that "wasn't working properly" . . . a psychedelic one that "you couldn't read."

At the inquest, she said she did see both Kennedy and Kopechne leaving together.

Q. Can you tell us when?

Newberg: 11:30

Q: What makes you say 11:30?

Newberg: I have a rather large watch that I wear all the time and I looked at it.

Why didn't she say that earlier when she volunteered to meet the press?

"I was always smart," she told a Washington Post reporter recently. "It [that question] seemed crucial to me in some way."

Newberg also noted that she was only 27 at the time of the interviews. "I was a kid is the point," she said. "I can't say it was out of caution or to be misleading. I was under pressure [in those interviews]. It was incredibly traumatic."

Chief Arena, now head of the police and fire departments in Lincoln, Mass., likes to finesse the chronological controversy these days by saying that the accident happened "sometime between 11:30 p.m. and 12:45 a.m." He points out that Sylvia A. Malm, a college student who was staying at the cottage nearest Dike Bridge, heard a car going by fairly fast, apparently in the direction of the bridge, sometime between 11:15 and 11:45 p.m. while she was reading in her bed. Her mother also heard a car "going faster than usual toward the Dike" around the same time. Both heard nothing more, but both also went to sleep around midnight.

All this, Arena agrees, could mean that Kennedy's car was bouncing toward the bridge when the Malms heard it and then it drove down that way again after Look spotted it. On balance, Arena feels that Look saw it last.

"I think the weight of it would probably go towards Huck because he was a deputy sheriff and he knew what time he got off work," Arena says.

The unsettled issues have filled books. Some of the others: WHY DID THE ACCIDENT HAPPEN?

In an initial statement to police that Kennedy and Markham took about an hour to compose on July 19, the senator said that he was "unfamiliar with the road." He said he was "on my way to get the ferry back to Edgartown" but mistakenly "turned right onto Dike Road instead of bearing hard left on Main Street."

In an accident report filed four days later, Kennedy estimated his speed at 20 mph.

At the inquest, on Jan. 5, 1973, the senator said he did notice at some point that he had turned onto an unpaved road but he insisted that he still didn't realize it was the wrong one. He said he didn't see the 10 1/2-foot-wide bridge until "a fraction of a second" before he got to it and he did't notice that a sharp left-angle turn was required to get onto the bridge until it was too late. "It appeared to me at the time that the road went straight," he said.

The court: Were you looking ahead at the time you were driving the car, at that time?

Kennedy: Yes, I was.

The court: Your attention was not diverted by anthing else?

Kennedy: No, it wasn't.

The court did not believe him. In a terse, 12-page report made public on April 29, 1970, District Judge James A. Boyule concluded that "Kennedy and Kopechne did not intend to return to Edgartown at that time; that Kennedy did not intend to drive to the ferry slip and his turn onto Eike Road was intentional."

In reaching those conclusions, Boyle observed that Kennedy "rarely drove himself" and that Jack Crimmins, his chauffeur of nine years (who is now dead), was readily available at the time of the fatal trip.

Kennedy told only Crimmins that he was leaving for [the] Shiretown [Inn]," the judge continued, and "Kopechne told no one , other than Kennedy, that she was leaving for [the] Katama Shores."

(The senator had checked into the Shiretown earlier in the day; Kopechne had registered at the Katama Shores motel two days earlier.)

The judge also emphasized that Kopechne had left her pocketbook behind at the cottage and did not take a key to her motel room with her. Esther Newberg, her roommate for the weekend, had one. Kopechne didn't ask her for it.

As to whether they knew of the dangerous bridge to be crossed, Boyle observed that Kennedy had been driven over the main paved road three times earlier on July 18, and over Dike Road and Dike Bridge twice. Kopechne, who had also been at the cookout cottage the previous night, July 17, had been driven over the paved roads five times and over Dike Road and Dike Bridge twice. NEVER BEEN TO CHAPPAQUIDDICK BEFORE?

The question arose instantly when Kennedy's statement that he was "unfamiliar with the road' became public on the afternoon of July 19, 1969. At the inquest, under oath, the senator went much farther, under questioning by Dukes County District Attorney Edmund Dinis.

Q. Now, were you familiar with the island of Chappaquiddick? Had you been there before?

Kennedy: Never been on Chappaquiddick before that day.

Dinis was puzzled. He thought Kennedy had said in a statement made before the inquest that he had been visiting the island for 30 years. Kennedy replied that he had been talking about Martha's Vineyard. Dinis tried once again.

Q. But you had never been to Chappaquiddick?

Kennedy: Never been to Chappaquiddick before 1:30 p.m. on the day of July 18th.

That was it. There was no elaboration. Yet Kennedy now concedes that he had been on the "beach part" of the island before, only once, he says, probably sometime in the 1960s. He thinks he visited it once again sometime after the accident. Asked to elaborate on any earlier pre-1969 visits, the senator told The Washington Post:

"Well, I think the inquest has the best information on that. I think, 'to use the facilities,' was my testimony."

Told that the inquest record contained no such information, Kennedy said he had anchored off Chappaquiddick in his yacht a number of times over the years. On one occasion, he said he went ashore to the Chappaquiddick Beach Club "where I tried to use or did use the facilities" since his yacht, the Victura, had no head, or toilet.

Kennedy said he had also come off his yacht to go swimmin in the Beach Club area -- on the north side of the island not far from the ferry slip -- but had never gone beyond the environs of trhe Beach Club itself, never gone swimming at any of the other beaches, never used the ferry, and never traveled any of the island's roads. He said he "interpreted" the question at the inquest to be one of familiarity with the island and not the limited confines of the Beach Club.

Reporters dispatched to Chappaquiddick after the accident had no trouble finding individuals who asserted that Kennedy had indeed been there before, including a former ferry operator who said he had taken Kennedy across, "possibly several times," in the ferry between 1955 and 1963.

According to Kennedy, such reports are "categorically untrue." Despite "all the investigation," he said no one has come forth to say that Kennedy had been at some particular home or some other point on the island other than the Beach Club.

The day after The Post interview, Kennedy's press aide, Tom Southwick, called to point out that the senator had told the Boston Globe in 1974 of his attempt to "use the facilities" at the Beach Club. That excerpt, however, also raises questions.

Kennedy told the Globe:

". . . I had never been on the island before, other than the occasion where I either landed on a boat or swam into that beach club that is right opposite the lighthouse there, to try and us the facilities some years before and was turned down. That was the first occasion that I had ever visited that island and ever traveled on those roads." DID KENNEDY ENTERTAIN THE IDEA OF ESTABLISHING AN ALIBI?

Kennedy has repeatedly said that he should have reported the accident sooner. He has said there were "a thousand different things" he should have done differently and that his conduct after the accident was "irrational and indefensible and inexuscable and inexplicable." In an extraordinary television statement July 25, 1969, he said he kept hoping that Mary Jo would somehow turn up alive, wondering whether "somehow the awful weight of this incredible incident might in some way pass from my shoulders.

"I was overcome, I am frank to say, by a jumble of emtion -- grief, fear, doubt, tortune, panic, confusion, exhaustion and shock."

Suspicions that he also might have thought of establishing an alibi were fed by his avoidance of lighted homes and an open fire station as he walked back to the cottage after the accident, by his swim back to Edgartown and his encounter with the innkeeper to ask what time it was, by his return to Chappaquiddick the next morning and by Markham's statement to the ferry operator then that "we just heard about" the accident.

Columnist Jack Anderson fuelded speculation Aug. 13, 1969, with an account that he said was "drawn painfully from Kennedy inimates." Anderson claimed that when Kennedy returned to the cottage and told Gargan and Markham what had happened, "gargan agreed to say he had driven the death car." It was only the next morning, when they learned the car had been found, Anderson asserted, that Kennedy reached "his moment of truth . . . abandoned this scheme and manfully owned up to what he had done."

Kennedy denounced the report then as "categorically untrue" and so did Gargan. But it surfaced again, in a four-part series in the Boston Globe. Quoting what it called "a highly knowledgeable source," the Globe said Gargan "agreed at one point to take responsibility for the accident," but the plan "was abandoned shortly before Kennedy reported the mishap to police."

In his interview with The Post this month, Kennedy once again declared that there was no truth to such talk. He said he never even fleetingly entertained the idea of an alibi. HOW MUCH DRINKING TOOK PLACE AT THE COOKOUT?

All the partygoers testified very little liquor was consumed at the cookout. Kennedy said he had only two rum and Cokes all evening. Most of the others said they had one to three drinks each and Gargan said he drank only Coke. Kopechne would appear to have had more than anyone else. A chemical anaylsis showed that she may have had as many as five one-ounce drinks of 80- to 90-proof liquor within an hour before she died, more if she had been drinking over a longer period.

Kennedy said he was "absolutely sober" when he left. Esther Newberg said Kopechne was, too. "Five or six drinks would have been completely out of order with the way she lived," Newberg testified. But she also testified at first that "I didn't see her [Kopechne] drinking . . . She may have had a glass in her hand, but I don't know what was in it."

Newberg, the only witness to be recalled to the stand during the inquest, was asked two days later by Judge Boyle whether she had seen Kopechne "drink any intoxicating liquor." Newberg said, "Yes."

Chauffeur Crimmins said Kennedy told him around 11:15 p.m. that "he was going to take Miss Kopechne back, that she wasn't feeling well." Crimmins said "she was bothered by the sun on the beach that day."

Kennedy says he doesn't remember telling Crimmins Kopechne was ill. Asked if she looked ill, the senator told The Post: "No, I don't remember now . . . I have no recollection 10 years later of what the true situation looked like."

Reporter: Did she indicate any reason --

Kennedy: No.

Reporter: -- for wanting to go back to the hotel, other than just 'I want to go back'?

Kennedy: I think that's about, that's about it.

The amount of liquor that Crimmins said he took away from the cottage after the tragedy, compared with what he brought there, suggests that much more liquor was consimed that Friday night than anyone admitted. However, there was also a gathering at the cookout cottage Thursday night, July 17.

Nine poeple were there, according to snippets from the inquest record, and at least some of them drank from the liquor supply that Crimmins brought from Boston. But most of Kennedy's friends and companions that week are still silent about the drinking, even when innocent explanations are sought.

"I really can't help you," Boston lawyer John P. Driscoll Jr. said last month. "It was so long ago."

Of the nine who gathered at the cottage Thursday night, Driscoll was the only one who did not return Friday. He said he "probably had a rum and tonic" Thursday, but he refused to discuss how much other drinking took place, even to clear up the questin of the missing liquor.

"I prefer not to," he said. ?It's ancient history." Did massachusetts law enforcement and judical authorities bend over BACKWARD FOR KENNEDY?

The Edgartown police investigation was inadequate, although Chief Arena contends it was not his fault. He says he didn't even find out about the cookout party until the partygoers had cleaned up the cottage and left the island. He did talk to Rosemary Keough briefly when she called about retrieving the purse she'd left in Kennedy's car on an earlier trip during the party. But the chief neglectged to ask her how the purse got there. Nor did he ask Kennedy why he hadn't reported the accident promptly.

"The only one I ever got to talk to was Jack Crimmins," Arena said. He said he asked a Massachusetts state police lieutenant assigned to District Attorney Dinis to help find and inteview the others before the July 25 hearing, but found out that the officer had no such intention. "That kind of shattered me," Arena recalls.

Kopechne's body was shipped hurriedly back to Pennsylvania with the assistance of a Kennedy aide before Dinis decided, too late, to seek an autopsy. The inquest was closed to the press and public by order of the Massachusetss Supreme Judical Court on a petition by Kennedy's lawyers.The state's high court also decreed that the records of the inquest could not be made public as long as Kennedy faced any danger of criminal charges. The court acknowledged that other inquests had been made public in the history of the Commonwealth, but said those had not usually been "of general interest."

In his report on the inquest, which he completed Feb. 18, 1970, Judge Boyle suggested that Kenedy ought to be prosecuted for reckless driving. The judge found "probable cause to believe that Edward M. Kennedy operated his motor vehicle negligently and that such operation appears to have contributed to the death of Mary Jo Kopechne."

Under Massachusetts law, Judge Boyle was charged with ordering the arrest of anyone accused in his report of committing a crime.The statute says: ". . . if a person charged by the report with the commisiion of a crime is at large, the magistrate shall issue process for his arrest."

The judge chose not to do that, for reasons he has never explained. That left the case to the Dukes County grand jury, whose members had been eager to review it for months. But when they convened in April 1970, they were lectured for an hour by Superior Court Judge Wilfred J. Paquet, who had come down from Boston to keep them in line. With a Roman Catholic priest at his side, Paquet told the jurors they were completely "subservient" and that he would permit no appeal of his rulings. The jurors gave up the next day after Paquet ruled that they could not even see the inquest records, including Boyle's report.

With the prospect of criminal charges against Kennedy eliminated, the Supreme Judical Court later that month approved release of the inquest records. Kennedy responded with a brief statement:

"At the inquest, I truthfully answered all questions asked of me," he said. "In my personal view, the inferences and ultimate findings of the judge's report are not justified and I reject them. . . . For myself, I plan no further statement on this tragic matter."

Kennedy was asked this month if he felt the courts might have shown him so much favoritism that this itself engendered continuing suspicions.

"No," he said. "I think that the process worked. As I say, I'd always like to relive that evening . . . The sense of tragedy and loss continues, but I was fairly treated." NEXT: The impact of Chappaquiddick.