A nuclear power plant worker suspected of strangling his wife and daughter and then killing himself had been placed on leave from his job to deal with mental problems, the plant owner said Tuesday.

Steven Lessard, an engineer at Unit 2 of the Indian Point Energy Center, killed his wife, Kathy, 48, and 14-year-old daughter Linda in their bedrooms, then killed himself, state police said Monday. It was not clear how Lessard died, police said.

Police found the bodies Monday after being called by relatives concerned that they could not reach the family by telephone. Authorities said the killings apparently happened late Thursday or early Friday.

Jim Steets, a spokesman for Entergy Nuclear Northeast, which owns the Indian Point complex in Buchanan, said Lessard dealt with planning projects and had no connection with the operation of the nuclear reactors.

Lessard, who had worked at the plant since 1995, would have undergone psychiatric testing when first hired and have had regular background checks since, Steets said.

Fellow workers noticed on Feb. 8 that Lessard "was overly stressed and just behaving somewhat irrationally at work."

A supervisor sent Lessard to a nurse at the plant. Lessard declined help within the company's employee assistance program, saying he was already seeing a doctor, but agreed to a leave of absence, Steets said.

"They thought it would be good if he could just take some time off to deal with what was bothering him," Steets said.

Lessard had an appointment with a psychologist or psychiatrist last week, Steets said, but "we don't know whether he saw that doctor."