Alexander Williams Jr., the state's attorney for Prince George's County, held a sheet of paper in his right hand, and thrust it forward. "You see this?" he said angrily. "Now read what it says."

It was a copy of a letter sent by Howard University to the law office of Arthur A. "Bud" Marshall Jr., the Republican hoping to unseat Williams as the county's top prosecutor. Marshall, who held the post for 24 years before losing to Williams in 1986, has infuriated Williams by casting him as a political opportunist, biding his time as prosecutor while planning a bid for higher office. Among other allegations, Marshall has accused Williams of devoting too many hours to teaching at Howard's law school and not enough time to managing his staff.

The letter from Howard said that from 1987 to 1989, Williams was an adjunct faculty member who taught one course each semester.

"One course," Williams said. "This is what I mean by a campaign of lies and distortions." Williams, who said he is frequently asked about his political plans, said he has made none beyond this election.

"He has no issues," Williams said. "He has nothing to talk about. We've done the job. We have all the endorsements. We have labor, the teachers. We have the people. And who does he have? No one. And so what he's done is resort to a mean-spirited, personal campaign of distortions and lies."

Marshall, blunt and sometimes hot-tempered, lost the support of the county's largely white Democratic power structure in 1986 after serving six terms as a Democrat and narrowly losing to Williams in the primary. The local party hailed Williams, the first black elected to a countywide office in Prince George's in more than a decade, as the more cautious, reform-minded, prosecutor needed at a time when the county's black population had reached about 50 percent.

"The problem is, he still thinks this is his job," Williams said of Marshall, who switched to the GOP this year rather than face the incumbent in another Democratic primary. "He doesn't want to believe that the voters of Prince George's were astute enough to make the right choice four years ago."

Williams, 42, who projects a staid and cerebral image compared with Marshall's outspoken, occasionally contentious nature, has kept a much lower profile in the Upper Marlboro courthouse than his predecessor. Much of what he has accomplished has gained little public attention, Williams said, yet has allowed the State's Attorney's Office to run far more efficiently.

"I think I'm more modern than Mr. Marshall," he said. "You had to see what I saw when I came into this office. I saw an office run by hand. There was no automation, no computers, nothing. Now we're computerized. I saw furniture that looked like it was from the 1950s. That's changed. I don't think it's right for victims to come in and sit around on old church pews . . . .

"His time has passed," Williams said. "Morale is so much better now. He was a terror on people around here. I'm a little more laid back. I'll delegate a little more. I believe in treating people as professionals, and not hollering at them or sending out nasty memos to the them, as he did."

Besides criticizing Williams's teaching schedule, Marshall has accused him of being "soft on crime," saying the incumbent seems more eager to "protect the citizens from the system" than to jail offenders.

He cited the most controversial case of Williams's tenure, that of Gregory Habib, a native of Ghana who died in a May 1989 struggle with four white police officers. Williams criticized police, a grand jury and some members of his own staff after the case ended in misdemeanor indictments.

Williams's remarks cost him the endorsement of the county's police union, which made no recommendation this year. "I was simply not satisfied with the way that case was handled," he said. "It's unfortunate that the rank-and-file {police officers} put so much emphasis on that. But I did what my mind told me to do. I wasn't satisfied that there was a thorough investigation, that the case was untainted. I have to review those cases to the best of my integrity, and that's what I did. They may not like it, but that's the way it is."

Williams contrasts his handling of the Habib case with Marshall's handling of the investigation of the cocaine-induced death of University of Maryland basketball star Len Bias.

Critics, locally and nationally, complained during the 1986 case that Marshall was directing a broad, overzealous probe of drug use on the College Park campus and making incautious public remarks about the investigation.

"That a key difference between us," Williams said. "I came in, and from the first day, I put a press policy in place. We're not going to comment on pending cases. That's the rule, and we follow it."

He cited other examples of what he called his more progressive approach to law enforcement. Where Marshall's administration sought the death penalty in every case in which the law allowed it, Williams said, his office seeks capital punishment only after a committee reviews the facts of each case.

Williams also said his office has been more aggressive in moving to seize vehicles from drug dealers. "You know how many cars Mr. Marshall seized in his last year? Six . . . . We're seizing over 200 cars a year," Williams said.

Marshall has accused Williams of misspending county funds by producing a midterm report on his adminstration that, to Marshall, seemed more like a campaign advertisement. And he has said publicly that Williams and his wife, Joyce, control "$1.7 million to $2 million in real estate."

"More lies and distortions," Williams said.

Williams has an advisory opinion from the Maryland State Prosecutor's Office, which said that spending government money for the midterm report was not improper. As for the real estate, he said most of it is being used by his wife, who operates three day-care centers.

"And what Mr. Marshall intentionally does not say, is that all of it is mortgaged," Williams said, adding that he and his wife have usually purchased one piece of property a year since the mid-1970s. "That's our style of investing. It's all proper, and it's all aboveboard, and I don't know why it was necessary for him to make statements about it."

Then he said, "I know why he does it. It's his pride. He wants his old job back . . . . But I don't think the majority of citizens are going to be fooled by his tactics. They won't bring Mr. Marshall back, because they know what that would be: It would be a step backward."