Philadelphia ? A nurse suspected of killing patients in two states was able to keep his license, even after he was fired from several jobs, because hospitals, prosecutors and state regulators didn’t share information.

Charles Cullen told authorities this month that he gave lethal injections to 30 to 40 critically ill patients during his 16-year career in New Jersey and Pennsylvania.

His public defender, Johnnie Mask, has since said Cullen — charged with one count of murder and one count of attempted murder in New Jersey — would not cooperate unless prosecutors guaranteed they would not seek the death penalty. Prosecutors haven’t said what punishment they intended to seek.

Cullen, who told authorities he gave the fatal overdoses of heart medication to put seriously ill patients out of their misery, had a history of work troubles.

He had been fired from two of the four New Jersey hospitals where he worked before moving to Pennsylvania in the late 1990s. At a third, he was one of several nurses questioned in the suspicious death of a 91-year-old patient.

In Pennsylvania, Cullen was fired from a nursing home for allegedly medicating patients at unscheduled times. A co-worker accused him in a lawsuit of giving a patient a dangerous, unprescribed shot of insulin.

One Pennsylvania hospital suspended him amid suspicions that he had hidden potentially lethal heart medications. Prosecutors investigated suspicions that he improperly drugged patients, but could not link him to any deaths.

But because Pennsylvania health care facilities and law enforcement agencies are not required to alert licensing officials of suspected misconduct, only St. Luke’s Hospital in Bethlehem ever filed a complaint about Cullen with the state nursing board, officials said.

Without official complaints, generally no action will be taken against a nurse’s license, said Department of State spokesman Brian McDonald.

“The nursing board can’t actually go out and police the actions of every single nurse in the commonwealth,” he said. “There are just too many.”

The state’s Bureau of Professional and Occupational Affairs has about 45 inspectors to investigate allegations of licensed individuals, and they cover many areas in addition to nursing.

Hospitals and nursing homes are required, in some circumstances, to report staff misconduct to the Department of Health, which licenses institutions but has no direct oversight of individuals.

The health department has the power to sanction hospitals, but it isn’t required to pass on concerns about a nurse’s conduct to licensing officials, said spokesman Richard McGarvey.

The Liberty Nursing and Rehabilitation Center in Allentown, which fired Cullen in 1998 for allegedly giving medications at unscheduled times, said it notified the Department of Health, but McGarvey said there was no record of that report being passed on to the nursing board.

Prosecutors also aren’t required to report alleged wrongdoing to licensing officials or to potential new employers.