The Virginia Department of Corrections has concluded that no patterns of sexual assault, harassment or fraternization exist at the Fluvanna Correctional Center for Women, even though 13 prison employees either have been fired or have resigned because they were found to have violated prison rules.

The investigation, conducted by the department's inspector general's office, began in October after an Associated Press report detailed the complaints of several inmates about treatment in the prison, which opened in April 1998.

The report, a review of 44 inmate complaints, concluded that the accusations made in 13 of them were true but that the episodes were not connected and that conditions at the prison were satisfactory. "We found that the incidents of sexual assault/harassment at FCCW were random and not indicative of a pattern of inappropriate behavior," said the inspector general's report, released Monday.

Although the investigation found no pattern of wrongdoing, the report suggested increasing video surveillance, rotation of guards and other changes to prevent problems.

Relations between security officers and inmates have come under increased scrutiny in recent years as lawmakers and prison officials have moved to ensure security at prisons and protect the rights of inmates. In July, a state law took effect that makes it a felony for a prison staff member to have carnal knowledge of an inmate.

Advocacy groups for better prison conditions criticized the report and called for an outside investigation.

"We didn't have high expectations of this investigation," said Susie White, chairwoman of Friends of Incarcerated Women. "After all, it was done by the Department of Corrections."

White also criticized the department for investigating only the Fluvanna prison, instead of all women's facilities in the state. The Fluvanna prison, about 20 miles west of Charlottesville, houses about 900 inmates, some of whom are serving life sentences.

Elizabeth Alexander, director of the National Prison Project for the American Civil Liberties Union, pointed out that 18 of the 114 male security officers at the prison were found to be guilty of some violation, and she said the ACLU would consider a lawsuit if more is not done. "I cannot imagine how they can say there's not a pattern," she said.

Alexander also criticized the report for not including details of each investigation. "Because there's no detail about the individual 18 cases in which something wrong occurred, it's even harder to conclude there's no pattern," she said.

Gary K. Aronhalt, Virginia's secretary of public safety, said he was satisfied with the findings and that there would be no further investigation into the matter. "This is over," he said.

The inspector general's report said that the 13 complaints found to be true involved four cases of sexual assault or harassment and nine cases of fraternization between staff members and inmates. Investigations of six of the 44 complaints are still pending, and eight complaints were determined to be unfounded. Inquiries into two cases were inconclusive. The inspector general's office referred 15 complaints back to the prison warden because they were determined to be minor.

In addition to the 13 employees who resigned or were fired in connection with the incidents, five others were disciplined, the report said. The report also stated that five of the cases have been passed on to the Fluvanna County commonwealth's attorney and that one former employee has been indicted.