Last April, an Army counter-intelligence agent was found with electrical wiring wrapped around his upper arms and plugged into a wall socket at a Holiday Inn in Jessup, Md. The wire had been cut from a lamp in the room and stripped of its insulation. The agent, Chief Warrant Officer III Ralph J. Sigler, was dead of electrocution.

Maryland police and Army authorities investigated and concluded that the death of the agent, whose job was to sell misleading information to the Russians, was a suicide. But, Sigler's widow and a lawyer she has retained see something else behind the death: a bizarre and chilling spy story and a mystery about the often controversial activities of America's secret spy organizations.

Sigler's widow, Ilse, who lives here in El Paso, recalled the last telephone call she received from her husband. The agent, his voice laboring and fighting the screech of some kind of electronic apparatus in the background, managed to croak out these words: "JUST LISTEN TO ME! Get you a respectable lawyer . . . Sue the U.S. Army. I'm dying. I never lied." Then the phone went dead. It is a tangled story - whomever one believes - and it is complicated by the ease with which elaborate conspiracies can come to mind in the field of intelligence, a field veiled in secrecy and official "no comments," where sources in one spy agency label another agency's version "disinformation."

Mrs. Sigler, 49, who is German-born and speaks fluent if somewhat broken English believes Army intelligence has done "something wrong," that her husband knew too much about it and that Army personnel murdered him for this reason.

Her lawyer, Sidney Diamond, thinks this may be possible, but he is also exploring the possibility that Army actions drove Sigler to suicide.

Diamond said that a former Army intelligence man, who knew Sigler, told him there "no way" Sigler - a generally clam, polite man - would have killed himself. This intelligence man told Diamond that torture and electrocution by wiring a victim the way Sigler was wired is practiced by "certain foreign powers" - a reference, Diamond said, to the Soviets.

Mrs. Sigler believes that her husband's death may fit into a pattern of deaths of American intelligence agents beginning in 1975, but extensive checking by the The Washington Post with authorities here and in Washington disclosed no connection between her husband's death and anyone else's. In some cases, there was no official record of deaths Mrs. Sigler had alluded to.

Indeed, after numerous interviews with Mrs. Sigler, polite, intelligence community sources and others, as well as a study of documents and reports dealing with the case, no completely consistent explanation for what happened can be pieced together.

Official sources offer little enlightenment. An Army spokesman in the Pentagon, for instance, said it would be "inappropriate" to comment on the case. Sources in Washington close to the CIA said they think any U.S. government complicity in Sigler's grisly death is "highly improbable."

Army psychiatrist subsequently examined the case and concluded in an official report - made available to The Post by Diamond - that Sigler "was not mentally responsible at the time of the act which caused his death."

An Army version of the story was, however, offered to Mrs. Sigler's first attorney by D.B. Grimes, who identified himself as chief of the special operations branch of the U.S. Army Intelligence Agency (USAINTA), according to Diamond, her second attorney.

According to that account. Grimes said that Sigler was an extremely effective and capable double agent responsible for "disclosing to the Army 14 previously unidentified Soviet KGB (secret police) agents.

Grimes confirmed that Sigler's job for 10 years was to sell information to the Soviets about U.S. radar and missile systems - information carefully concoted by the Army to mislead the Russians, Diamond said.

Grimes told the attorney that Sigler flunked a routine polygraph test in March. Subsequent questioning beginning April 4 at Ft. Meade convinced U.S. officials that Sigler had told the Russians more than he should have, Grimes indicated.

Sigler did this, Grimes said, because he had fallen in love with the intelligence game and wanted to stay in it at a time when the Russians were berating him for the low quality of information he was selling them.

Grimes said the Sigler has trouble remembering exactly what he had told the Russians. Since Sigler died alone in his hotel room before disclosing everything he told the Russians, the Army was faced with the impossible task of trying to take counter measures against the results of Sigler's unknown divulgences, Grimes told the attorney.

According to Grimes. Sigler had a "loose tongue" when drinking and U.S. agents learned that the Russians had gotten Sigler drunk. Sigler was told during his Ft. Meade questioning, according to this version, that he would never again be able to function as an agent - a factor that might have driven him toward suicide, in the Army's account to Diamond.

Mrs. Sigler thinks her husband was beaten, possibly tortured and murdered, after he was put through a lengthy series of polygraph tests at USAINTA's offices.

The day before he died, he told his wife cryptically over the phone, "I guess I got into some trouble, but it's not us, it's them. If the tests go well today, they'll let me go tomorrow. Be a good girl."

Police and Army investigators reported the Sigler was founded sprawled on the floor of the motel room fully dressed. A 12-foot length of two-ply electrical cord had been cut from a lamp in the room and then stripped of insulation leaving two bare wire ends. One was wrapped around each of Sigler's upper arms, and the other end of the cord was plugged into the wall socket.

An Army intelligence agent and the motel's night manager discovered the body. A chair had been placed on top of another one near the light switch, and police theorized that Sigler sat on the top chair and flipped the light switch to activate the socket into which he was plunged.

He may then have been thrown to the floor, according to the official view, although officials have no comprehensive explanation for why such an unusual procedure might have been followed.

According to investigators, Sigler left this note in his hotel room written in longhand on hotel stationery:

"1. I don't know what I'm guilty of.

2. Then why the positive response?

3. Acting?

4. Lying?

5. Don't know the difference?"

6. Too bad!

I've given up all hope. I wish I knew. I wish I knew. I tried too hard. I'm dead."

Mrs. Sigler hired Diamond, a corporate affairs attorney who usually steers clear of criminal cases, to mount a lawsuit. Diamond, 36, said he was a highly paid Dallas attorney until a few years ago when he moved here to get out of the rat race of the big city.

Diamond said he though Mrs. Sigler was "crazy" when she first came in with her story, so he charged her a stiff fee. Events befalling him and others since he took the case have helped change his mind.

Diamond said that private investigators and others who visit Mrs. Sigler's house here have been followed by cars bearing Army stickers.

Diamond's house was broken into twice after he took the case, he said, and although there was valuables on the premises, nothing was taken.

Mrs. Sigler said her house was broken into last week and a roll of film belonging to her lare husband was stolen after she had mentioned the film in a telephoned conversation with a private investigator she retained.

The pattern of events that contibutes to Mrs. Sigler's deep suspicions intensified in January, 1976, she said. An Army warrant officer whom Sigler worked with here and who, he had indicated indirectly to his wife, also worked in intelligence, was found shot to death in the desert near the White Sands missile range north of here, said Mrs. Sigler.

Mrs. Sigler recalled that the shooting was deemed a suicide by authorities, but her memory of the details was imprecise. Despite extensive checking by The Post with civilian and White Sands authorities, no such death could be vertified.

"He (Sigler) didn't believe it (the death of the warrant officer) was a suicide," she said. "My husband said, They're killing agents. There's conspiracy among their own people. They're having problems I said, 'You know who's killing them. It's your own people.'"

Sigler was an electronics specialist at the Air Defense School here at Ft. Bliss - an assignment that gave him an excellent cover for his counter-intelligence activities. The 47-year-old agent was born in Czechoslovakia and joined the Army when he was 17, serving in various posts here and abroad until he becomes a counter-intelligence agent in 1968.

Sigler and his wife were assigned to Germany between 1968 and 1970, and during that time he traveled frequently to Switzerland and elsewhere to meet with Soviet agents, Mrs. Sigler said.

One time in 1969, she said, he came back for the first time from Zurich with money, about $3,000 in $20s and $50s that he said the Soviets had paid him for information. He turned the money over to his Army superiors, Mrs. Sigler said. She said the he obtained about $100,000 this way over the years and turned it all in.

From time to time U.S. agents would return money to him for trips or to buy things like a new car to make it appear to the Russians that he was living high on money they gave him, she said.

After he was stationed against at Fort Bliss. Sigler made trips to Mexico every three months to contact the Soviets, Mrs. Sigler said. Things went smoothly until 1973 when he has one assignment the he didn't like, she said.

"He came back upset that time, and that night we sat on the floor in front of the TV and he said, 'I don't like what they make me do this time'" his widow said.

"Who?" she asked.

"They made me to sell my country," he replied. "I don't like that."

But he said little more, only that, "it's getting too deep, what I have to do for them."

Sigler then requested an assignment to Korea and spent a year there, leaving his wife here. He returned in 1974 and it was then, she recalled, that the trouble really started.

"I noticed I was followed," she said. "Sometimes it was Army people with Army stickers on their cars. I told my husband, 'I'm upset. If it goes on like this I want a divorce.' He replied, "There's nothing to worry about. Just ignore it. You'll probably be followed by both sides.'"

At one point in 1974 Mrs. Sigler said, the Siglers were required to go on a family vacation in Europe where Sigler spent several days being polygraphed by the Russians. He returned relieved and with a large sum of money, saying everything was all right, she said.

In January of 1976 Sigler went on an assignment in Mexico, telling his wife, "they're having problems. If I don't come back, call (his Army contact). But you can't trust anybody anymore. They have a conspiracy among their own people."

He returned, however. Then, at some points during this period, a colonel began picking Sigler up each morning and driving him to White Sands.

"The colonel would come for him, looking up and down the street to see if anyone was following," said Mrs. Sigler. She knew something was wrong but her husband wasn't saying what.

In March 1976, Sigler was summoned to San Francisco, she said, where he apparently met with both the Soviets and with U.S. agents. He flunked a polygraph test administered by the U.S. agent and was very concerned when he returned home, she said.

After failing the test Sigler was summoned to Ft. Meade, Mrs. Sigler said. It was the last time she saw him alive.

She speculated that he had failed the test because he was writing a book on his intelligence experiences. Agents are not supposed to keep notes on their work, she said.

Several days before Sigler's death, while he was at Ft. Meade. an Army agent visited the Sigler's home and retrieved the manuscript, she said. Subsequent efforts to have the book returned were unsuccessful, she said.