The Rhode Island State Police have ended their seven-month sexual abuse investigation of the embattled St. George’s School without bringing criminal charges, officials announced Thursday.

“Unfortunately for those who came forward, they will not be able to seek justice within the criminal justice system due to the applicable statutes defining conduct and statute of limitations,’’ state Attorney General Peter F. Kilmartin and Steven G. O’Donnell, superintendent of the State Police and commissioner of public safety, said in a joint statement.

The investigation, they said, focused on allegations of sexual assault and misconduct by seven former faculty members, one current employee, and three former students. Detectives interviewed former students and former and current faculty, and reviewed documents.

They examined allegations that the current and prior school administrations did not report alleged assaults to the state Department of Children, Youth, and Families, as required for credible accusations of abuse.

“These allegations of failure to report could not be charged due to the fact that in some instances the alleged failure to report was not defined as a criminal offense until 1979, and in other instances, the prosecution of any allegations would be time barred by the three-year statute of limitations that existed for the specific crime,’’ the statement said.

Kilmartin and O’Donnell also noted that the decision not to file criminal charges was based on “the laws which defined the alleged conduct at the time it occurred. . . . The laws on sexual assault are much different today than existed at the time many of the reported incidents took place.’’

“For example, the statutes defining first-degree sexual assault [rape] were not enacted until 1979, and common law rape required the sexual assault to take place between man and woman,’’ the statement said.

At least two alumni at St. George’s have reported being raped by other male students, one with a broomstick and one with a lacrosse stick.

In a statement, the school said it was aware the attorney general had declined to pursue charges.

“St. George’s cooperated fully with the Rhode Island State Police’s extensive and thorough investigation. Our focus remains on efforts to support survivors and on continuing to make the school as safe a place as possible for our current students,’’ St. George’s said in a statement.

Anne Scott, a sex abuse victim and leader of SGS for Healing, said Thursday’s report pointed out holes in the criminal justice system.

“It highlights the urgency for reform for our civil and criminal statutes, both with regard to assault and mandatory reporting,’’ said Scott, 53, who heads a nonprofit foundation in Virginia. “The system can do a lot better for survivors.’’

Scott was 15 when she was allegedly first raped by athletic trainer Al Gibbs.

The Middletown prep school has 365 students in grades 9 through 12 and today charges $56,000 a year for boarders. It has been embroiled in a sex abuse scandal since December, when Scott and two other alumnae came forward publicly with sex abuse allegations.

The State Police began investigating St. George’s in early November, shortly after headmaster Eric Peterson sent a letter to alumni stating that school officials had identified “multiple credible reports of sexual misconduct at the school, ranging from unprofessional behaviors to outright sexual assault.’’ Most of those took place in the 1970s and ’80s, though some allegations are more recent and some are older.

At the urging of Scott, her attorney Eric MacLeish, and other victims, the school carried out an initial investigation of its own.

In late December, the school released a report saying it had found a total of 26 students were allegedly sexually abused by one of six school employees.

Though most perpetrators were fired, the school did not report them at the time to the Department of Children, Youth, and Families.

After victims learned that investigator Will Hannum was not only the law partner of the school’s then-outside counsel but also her husband, the school commissioned a second investigation by Martin F. Murphy, a former Middlesex prosecutor and a partner at the Boston firm Foley Hoag. His report is due in late June.

MacLeish and Carmen Durso, who are representing some of the victims, say they have received credible allegations that nearly 50 alumni were sexually abused — most by staff, some by other students.

MacLeish said Thursday that he was disappointed but not surprised by the Rhode Island report.

“Those four words, ‘the statute of limitations,’ deny justice in so many cases,’’ he said.

He added, “This report is not in any way a statement that these school officials did the morally correct thing or what was in the interests of the children.’’

Bella English can be reached at english@globe.com.