The American Civil Liberties Union filed a $425,000 damage suit yesterday against Prince George's County on behalf of a man who said he was raped in the county detention center.

The suit, filed in U.S. District Court in Baltimore, alleges that jail workers and county officials acted with negligence and/or deliberate indifference to the personal safety of the victim, Gerald Mohler, in violation of his constitutional rights.

The suit is the first of several that will be filed by the ACLU for men who were raped in the county jail, according to Steven Ney, chief staff counsel of the Washington-based ACLU prison project. "It's the county's responsibility to protect inmates assigned to their custody," he said. "They've known for years about violent sexual assaults committed by inmates against other inmates, yet they refuse to take elementary steps that they know they should take to prevent that kind of misconduct."

Deputy County Attorney Barbara Holtz said she could not comment on the suit because she had not yet read it.

Mohler, 21, was raped in 1980 while he was awaiting trial for armed robbery in the county jail, according to Mohler and two witnesses who were quoted in a series of articles in The Washington Post last September on rapes in the county jail. The series quoted jail inmates and guards as saying rapes and violent sexual assaults occurred about 12 times a week in the Upper Marlboro jail.

After the series, members of the ACLU prison project got in touch with the rape victims, most of whom had given their permission to be identified by name.

Mohler's rape occurred on March 18, 1980, about 6 a.m., according to the suit. Mohler was surrounded by three prisoners while he was in his cell, the suit said, and one of the prisoners told Mohler that he wanted his body. Mohler refused and the three prisoners jumped on Mohler, beat him with their fists, pulled his jumpsuit down and took turns raping him. Then another prisoner entered the cell and raped Mohler while the others held him down, the suit said.

When Mohler entered the county jail, the suit said, he should have been separated from stronger and more aggressive inmates. The suit also stated that during the rape, which lasted more than a half-hour, there was no guard in sight and no guard went to his aid. In addition, according to the suit, the guard station consisted of an enclosed booth that made it "difficult, if not impossible, for them guards to hear prisoners fighting or yelling."

The suit named as defendants Prince George's County, former county executive Lawrence J. Hogan, jail director Arnett Gaston, former jail director of security Gerald Rice, former jail shift commanders Edward Blakesley and Carlton Yowell, and three unnamed guards.

Last month, a county grand jury indicted four men on sexual-offense charges in connection with Mohler's alleged rape.