A 19-year-old car mechanic from Queens, N.Y., was near an Exxon station in Greenbelt last year when a window was broken in the station, sounding an alarm. He was arrested and charged with attempted breaking and entering. He claimed he was innocent, and the charge was later dropped for lack of evidence.

But the young mechanic paid a high price for being arrested. On the day of his arrest, March 26, 1981, he was taken to the Prince George's County Detention Center. Two weeks later, while in a locked cell with four other men, he was raped by two of them, John Turkette, 24, and Eugene Hawkins, 17, he told police and an assistant state's attorney. Turkette was serving a sentence for manslaughter, and Hawkins was in jail on a first-degree murder charge. Turkette and Hawkins denied raping him, but acknowledged beating him.

After the mechanic was taken to Prince George's General Hospital and a rape was confirmed, the young mechanic returned to the jail, where the men he accused of raping him followed him from cell to cell. First, jail guards placed him in the same cell with Hawkins and Turkette, who beat him and threatened to harm his family if he accused them in court of rape. Later, jail officials placed him in a locked cell across from the two men, who hit him over the head with a broom they shoved through the bars. The mechanic tried to commit suicide twice after his repeated encounters with Hawkins and Turkette, according to jail and court records, and was found to be "depressed and suicidal" by doctors at Prince George's General Hospital.

The mechanic's experience was not an isolated incident. Violent gang rapes and sexual assaults occur in the Prince George's County jail about a dozen times a week, according to guards and inmates interviewed by a Post reporter for this series. The rapes and sexual assaults usually occur in cells beyond the vision of a guard. Even when an inmate screams for help, guards often do not respond -- until it is too late.

Interviews with about 10 guards and 60 inmates show that the jail routinely places those most likely to rape with those particularly vulnerable. Those likely to rape are men charged with or convicted of violent crimes such as murder and armed robbery. Those likely to become their victims are men charged with nonviolent crimes such as shoplifting and driving while intoxicated. The jail has an official policy of separating the violent inmates from the nonviolent ones but, in reality, the policy does not work in the crowded facility.

In addition, those who are raped are often no better off once they've reported the rape. They are locked in a small cell with several other inmates -- the same tactic jail officials use to punish unruly inmates. Sometimes, as in the mechanic's case, those other inmates are the original rapists.

The director of the center, Arnett Gaston, says he does not believe that large numbers of rapes and sexual assaults occur in the jail. Gaston says there is no proof that many rapes and sexual assaults are unreported. Even when an inmate reports a rape, Gaston said, he does not believe it happened unless the inmate presses charges -- a rare occurrence.

During an interview two weeks ago at the jail, Gaston defended the jail's placement of inmates charged with misdemeanors in the same sections with those charged with violent crimes. "These people men charged with violent crimes are charged with, not convicted, of certain acts," Gaston said. "Under the law, they're technically innocent."

Jail spokesman Jim O'Neill explained further: "More than half of these people are charged with violent offenses. But with the population being what it is, there's just not enough space to classify everyone as far as charges." Two Assaults Alleged

Gregory Graham, 25, was arrested and charged with theft last year for shoplifting 15 records from the Musicland record store in Hyattsville. He did not have enough money to post $300 bond, so he spent a month awaiting trial in the Prince George's County Detention Center.

Graham was sexually assaulted on two different occasions, both times by men charged with crimes far more serious than his. The first time was on May 15, 1981, in a section of the jail known as 2A. Two of the men who he said forced him to perform oral sex were charged with first-degree murder. One of the men, who is a juvenile, said in an interview that after Graham walked into a cell, he and three other inmates blocked Graham's exit and threatened to beat him unless he followed their directions.

Graham reported that he was sexually assaulted but did not bring charges against the men; he said he was afraid of retaliation.

Partly as a result of Graham's complaint of a sexual assault, he was moved to the "cell block left" section of the jail, a section that jail officials feel is particularly safe because it is a small area and the guard sitting in front of it has a good view, according to jail Sgt. Cindy Barry.

While there, Graham complained of another sexual assault. The assault occurred on May 30 or June 1, according to a jail log book. In cell block left, three of the cells were locked. Inside those cells were men who had acted violently. For most of the day, the violent inmates could do no more than yell at the other inmates, who were in the common area of the section.

But for one hour each day, the violent inmates were allowed out of their cells -- for recreation -- in the section's common area. Graham was sexually assaulted by one of the violent inmates during recreation.

The assault occurred when an inmate named Joseph Roberts yanked Graham into his cell. Roberts, who was awaiting trial for armed robbery, was in the section because he had shot and wounded a jail guard, Joyce Williams, during an escape attempt from the county jail.

Roberts acknowledged in an interview that he sexually assaulted Graham.

"I pressed him against the wall and asked him for his body," said Roberts. "He said no but they always say no."

Roberts said that meanwhile he had exposed himself to Graham; Graham continued to resist.

Roberts opened Graham's jumpsuit, according to Graham, and began forcing anal intercourse. Then Roberts was interrupted by a friend, Warren Timothy Fletcher, who entered the cell. In an interview, Fletcher said he witnessed the sexual assault.

"When he Fletcher walked in," said Roberts, "I lost my hold and Graham ran out of the cell; he ran up the bars on the outside of the section and started screaming for help."

The guard, who no longer works at the jail, took Graham to the jail medic. The medic did not find evidence of a rape. Graham said he decided not to bring charges against Roberts because he was afraid that Roberts or his friends would harm him.

Today, Roberts feels no remorse about his actions. "I get tired of masturbating," he says. "Why should I masturbate when I got freaks who will do it for me? They look similar to a woman. Graham had female features."

At the jail, the two sexual assaults of Gregory Graham are not mentioned on the jail's list of "reported rapes," even though he reported them to guards who recorded the incidents in official reports.

Two days later, Graham pleaded guilty in District Court to stealing the records. Judge Louis Ditrani sentenced Graham to 30 days in jail, but gave him credit for the month he had spent there.

Graham is still troubled by the sexual assaults. "They acted like animals toward me," he says. Rec Period Attacks

On Jan. 17, 1981, Richard Puleo returned to his Bowie house to find a 21-year-old man standing in the first floor hallway, wearing his wife's jeans and shirt. Puleo phoned police, who arrested the young man and charged him with breaking and entering.

But the intruder says he did not intend to burglarize the house. On that cold winter day, he had walked 12 miles from his home in Edgewater, Md., because he wanted "time to think." Then he began shivering. "I broke in the house to get warm," the young man said at his home during an interview in which he asked that his name not be used.

Six months later, after psychiatrist Rolanda Vieta of Spring Grove Hospital diagnosed the young man as schizophrenic at the time of the crime, the charge against him was dropped.

Most of those six months were spent in the Prince George's County Detention Center, where the man was held in lieu of $1,000 bond. At the county jail, according to jail director Gaston, he was given a locked cell to himself for his protection because he displayed a "loss of contact with reality." Despite the locked cell, the man was raped on two different days within his first month in jail, according to the victim and two men who said they raped him.

The rapes occurred after a guard unlocked the man's cell so that he could have an hour of recreation -- time to wander in the section and mingle with other inmates. During the hour, as at other times, the guard is supposed to watch the inmates.

This is how one of the rapists, Wallace Parker Jr., 28, tells the story of the first time the young man was raped:

"Andre and Wondel two other inmates were on a top bunk playing cards. They asked the kid victim to go up on the bunk and play cards with them. The kid did. Then Wondel threw a blanket down the front of the cell, so no one could see anything. Wondel said, 'Come here, man, take your pants off.' The kid said no, so they hit him on the face and Andre took his pants off . . . . " Parker said he, Wondel Smith and a third man then raped the man.

At the time, Parker had been convicted of armed robbery and was awaiting transfer to the Maryland Penitentiary in Baltimore, where he is serving a 20-year sentence. His description of the rape was corroborated by Smith, who says he also raped the young man. Smith is currently serving a 40-year sentence for first-degree murder at the Maryland Correctional Institution at Hagerstown.

"I f----- him because there were no females at the time," said Smith.

Andre Martin, 22, who is currently serving a 20-year sentence for armed robbery at the Maryland Penitentiary in Baltimore, says he helped Parker and Smith rape the young man but that he did not rape him.

"Bam Bam Parker said, 'Come on, Andre, hold him.' So I held him . . . . The boy was screaming, he was saying, 'Stop, take it out, you crazy, I ain't no girl.' "

During an interview, the young man corroborated numerous points of the rapists' story. He did not report either of the rapes to anyone in the jail. Doctor Confirms Rape

The 19-year-old Queens mechanic was originally placed in Section 1A of the county jail where he was forced to perform oral sex, according to a witness and former inmate, Adrian Smith. The mechanic complained to Al Cohen, a jail counselor, that he had a "problem" with inmates, though he didn't specify what kind of a problem, according to jail spokesman O'Neill.

Soon afterward, jail officials put him into Section 2A of the jail because that section was for juveniles and less aggressive inmates, according to O'Neill.

But in his new section, the mechanic was sexually assaulted again -- by different men. The accused men, who denied the charge of rape, were both in jail for violent crimes. One, Turkette, had been convicted of manslaughter. The other, Hawkins, who was in the section because he was a juvenile, was charged with first-degree murder. In addition to Hawkins, Turkette and the mechanic, there were two other inmates in the locked cell.

Why was the mechanic in a locked cell with Hawkins and Turkette? According to jail officials, the mechanic was the aggressor in a fight and needed to be punished. But Hawkins tells a somewhat different story, saying that the mechanic was the victim in a fight and needed protection. Hawkins was in the cell, he says, because he beat up another inmate, and Turkette was in the cell because he was afraid of being sexually assaulted, according to spokesman O'Neill.

The second attack took place on April 16 at 4 a.m. Hawkins and Turkette woke the mechanic, according to the mechanic's statement to police, tied a bed sheet around his neck and tried to force him to perform oral sex. When he refused, Hawkins and Turkette allegedly took off his pants and forced anal sex with him.

The rape was confirmed by Dr. Harold Alexander of Prince George's General Hospital, who found numerous injuries to the mechanic's anus, according to medical records.

The mechanic declined to be interviewed by The Post. But his description of the rape was supported by two other inmates, Virgil McClung and Frederick Vlachos. They said in interviews that Hawkins and Turkette described for them how they raped him.

In an interview, Hawkins denied raping the mechanic, but then he admitted beating him up on the morning of the alleged rape and telling other inmates that he raped him. "I was only joking," said Hawkins.

Hawkins said he often harassed the mechanic. "I'd say, 'What's up, girl?' and pat his ass because he was big and goofy looking," Hawkins said.

Turkette denied that he ever raped the mechanic, but he admitted beating and harassing him, saying that he felt he had to go along with Hawkins or become a victim himself.

According to Hawkins and Turkette, the guard was in the glass booth adjacent to the mechanic's cell on the night of the alleged rape. But the guard, who no longer works at the jail, could not see into the cell, which is made of concrete. Turkette and Hawkins said that the last time they saw the guard that night was at 11 p.m., five hours before the time the mechanic said he was raped. At 11 p.m., a group of guards passed the cell to count the inmates. The next time Turkette and Hawkins remember seeing any guards was 7 a.m. -- three hours after the alleged rape.

After a rape was confirmed at the hospital, jail officials put the mechanic in a locked cell in a different section on the jail, known as the processing unit. He was in that cell for a couple of days when guards put two familiar inmates into his cell: Hawkins and Turkette. The alleged rapists were on their way to the police station, according to Hawkins, where police were going to interview them about the rape charge.

Hawkins and Turkette wasted no time in taking out their anger on the mechanic. "Me and Turkette beat him up," Hawkins said. "Turkette grabbed him and threw him in the corner. He fell against the wall and I hit him three or four times in the neck. The guards didn't come for five minutes."

Hawkins said that he and Turkette told the mechanic that they would harm his family if he accused them of rape in court.

At the jail, there is no record that Hawkins and Turkette were in the same cell with the mechanic. But a guard who was on duty at the time confirmed that Hawkins and Turkette had beaten the mechanic in the processing-unit cell.

After the guards took Hawkins and Turkette out of the cell, the mechanic tried to commit suicide by slicing his wrists, according to jail records. He then was taken to Prince George's General Hospital, where Dr. Adul Rermgosakul diagnosed him as "depressed and suicidal," according to court records.

When the mechanic returned to the jail, officials put him back in 2A, where he had been raped, in a locked cell by himself. Directly across from that cell, in another cell, were Hawkins and Turkette.

"We didn't have the capacity to put him in CBL another section of the jail ," said spokesman O'Neill.

Although Hawkins and Turkette were in a locked cell, it was unlocked for one hour each day. It was during one of those times that Turkette shoved a broomstick through the bars of the mechanic's cell and hit him over the head. Hawkins, for his part, says that he threw a cup of urine on the mechanic through the bars. The mechanic then made a second suicide attempt, according to jail records, by slicing his wrists.

On April 23, 1981, the mechanic went to court; the attempted breaking and entering charge against him was dropped for lack of evidence.

He went home to New York. He did not return to Upper Marlboro in October, when he was scheduled to testify in court against Hawkins and and Turkette in the rape case. As a result, the rape charges were dropped. Accepts 'Protection'

Gerry Mohler, 21, of College Park, was arrested and charged with armed robbery on Jan. 21, 1980, for robbing an Adelphi man of his watch and a pocket calculator in the man's apartment.

Two months later, Mohler was gang-raped while he was awaiting trial in the Prince George's County Detention Center, according to Mohler and two witnesses, Tommy Posie and Otis Praylow.

After he was raped, Mohler felt that he had only two choices: Either stay in a locked cell for 23 hours each day as protection from rape or do sexual favors for an inmate in return for protection. Ultimately, Mohler chose the second alternative.

Mohler, who is heterosexual and has a son, says that after his rape he was in a locked cell alone for several days. "I was miserable," he said. "It was like being in a locked telephone booth all day and all night."

Mohler asked jail officials to let him out. They obliged, and Mohler then joined about 40 other inmates in the jail's D1 dormitory area. While there, he constantly was sexually harassed by other inmates, who joined him in the shower, pinched him, fondled him, and threatened him with rape.

Mohler asked a jail guard to move him to a safer section of the jail, but the guard told him that he had to "deal with" the harassment because he already was in the safest section, according to Mohler and another inmate.

Mohler, who by then had been convicted of the armed robbery charge, says that he then had two alternatives: go back to the locked cell or allow a certain inmate, named Jerome Wilcox, to protect him from sexual harassment and rape.

Mohler said that Wilcox suggested the transaction by saying, "If you don't hook up with somebody you're going to have a hard time."

Mohler rejected the suggestion at first, but after several weeks of harassment he gave in.

"I only did it three times with him," Wilcox said. "And I didn't force him." THE SERIES

The Post studied 24 cases of male rape and sexual assault that occurred in the Prince George's County Detention Center from 1978 through 1982.

Twelve cases were chosen to illustrate different aspects of the problem.

County jail officials, prosecutors, defense attorneys and judges say they are aware that rapes occur at the jail. But the rapes continue, hidden from public view yet with serious consequences to society.

The rapists' names were obtained through interviews with victims. Most of the rapists were interviewed in Maryland prisons where they are now incarcerated.

A few, who are now out of jail, were interviewed in their homes. For the most part, they spoke freely about the rapes they committed, characterizing them as a routine part of jail life.

The victims' names came from sources in the jail and the Prince George's County Courthouse. Those mentioned by name gave permission for their names to be used. Most were interviewed in their homes.