MARSHFIELD, Mass. (AP) — The parents of the man charged in last week's office rampage in Massachusetts say their son has been hospitalized for depression, and was being treated at the time of the deadly shootings.

But Richard and Rosemary Martinez said Michael M. McDermott was in high spirits on Christmas Day, a day before he allegedly gunned down seven co-workers at the office of Edgewater Technology Inc. McDermott, 42, has been charged with first-degree murder.

"We had the most wonderful Christmas with him," Rosemary Martinez, 71, told The Boston Globe in an interview published Friday.

"I cannot comprehend that my son did this," said Richard Martinez, 72. "I think of the seven families who have been so horribly destroyed. We're devastated for these seven families."

Prosecutors have said McDermott was upset that the company was going to withhold part of his salary to pay back taxes. But his parents said they saw no signs that their son, who legally changed his last name in 1982, was having any kind of financial problems.

McDermott was a bright child and a self-taught computer whiz who could fix anything, his parents said. He worked on a submarine in the Navy, then got a job at a nuclear power plant, where he suffered his first mental breakdown.

His parents, who are retired teachers, said he was suicidal after a breakup with a girlfriend, and spent a month in a Massachusetts hospital undergoing treatment for severe depression.

"We have a very bad genetic family history of depression," Richard Martinez said.

McDermott was later hospitalized two more times. When McDermott joined Edgewater in March, he was on medication and was seeing a psychiatrist.