Lawyers for 49 people who say they were sexually abused by Dr. George Reardon during the three decades he practiced at St. Francis Hospital and Medical Center sued the Hartford Archdiocese Wednesday, claiming the religious organization shares responsibility for the abuse.

"It's our belief that as early as 1970, both the hospital and the diocese knew George Reardon was a monster and they did absolutely nothing to stop him," said New Haven lawyer Joel T. Faxon of the Stratton Faxon law firm, which represents the plaintiffs.

Nearly the entire 40-page lawsuit describes the abuse allegedly suffered by the plaintiffs and repeats legal claims made against St. Francis. But it also asserts that the hospital and the archdiocese were so closely aligned that they operated as "joint venturers and/or partners" to a degree that the archdiocese shares blame for Reardon's actions.

Two nuns served as executive director of the hospital from 1962 to 1988, controlling the hospital, the suit claims, on behalf of the archdiocese. One of the nuns also was a member of the hospital's research committee, which oversaw the growth study Reardon claimed to be conducting at the time the abuse took place. In addition, the archbishop has always served as chairman of the hospital's board of directors, according to the lawsuit.

As a result, the suit claims, Reardon was acting as an agent of not only St. Francis, but also the archdiocese.

"There is no way for the diocese not to have known the extreme danger Reardon posed to the children in the hospital," the law firm said in a press release announcing the suit.

A message for an archdiocesan spokesman was not returned Wednesday.

The 49 plaintiffs in the suit against the archdiocese are among 135 people suing St. Francis, alleging that the hospital was negligent in failing to stop the abuse. An effort to mediate the cases failed last week, and attorneys are preparing to bring the claims against the hospital to trial.

St. Francis officials have said the hospital did not know of the specific allegations against Reardon until 1993, when state health officials tried to revoke his license. Reardon died in 1998.

Evidence of his crimes were uncovered in 2007, when a homeowner renovating Reardon's former West Hartford home found more than 50,000 slides and 100 movie reels of child pornography. The photographs suggest he may have abused 500 children.

Paul T. Edwards, a lawyer for the plaintiffs, said the attorneys chose to move ahead with the suit against the archdiocese once it was clear the mediation with St. Francis would not resolve the cases. Under state law, victims of child sex abuse may bring lawsuits only until they turn 48, and Edwards said it was important to file the suit against the archdiocese before the statute of limitations ran out for the victims.

"We waited what we thought was an appropriate time to try to resolve these cases informally, but that didn't happen and now we have to protect these people," he said.