PARIS – A restaurant cook was sentenced to life in prison Thursday for killing and dismembering four people during a Labor Day weekend murder spree in western Maine last year.

Christian Nielsen, 32, pleaded guilty to four counts of murder last week in the deaths of three women and a man over a four-day period. Nielsen was a boarder at the Black Bear Bed & Breakfast in Newry at the time.

“I just want to say I’m sorry for what I did,” Nielsen said to the victims’ families, who filled five rows of benches in the courtroom, before he was sentenced. It was the first time he had expressed remorse publicly.

Prosecutors had asked that Nielsen be given four life sentences, calling it an appropriate punishment given the number of people he killed and the gruesome nature of their deaths. Defense attorneys had asked for a sentence of 45 years.

Justice Robert Crowley handed down four life sentences to be served concurrently after hearing emotional and tearful testimony from about 20 members of the victims’ families and relatives of Nielsen. Under Maine law, a defendant receiving a life sentence cannot be released from prison, meaning Nielsen will die behind bars.

“When all is said and done, Christian Nielsen has committed four of the worst criminal acts in recent Maine history,” Crowley said.

Nielsen first shot James Whitehurst, 50, of Batesville Ark., in a remote wooded area on Sept. 1, 2006, then dismembered his body and burned the remains the next day. Whitehurst was a handyman who also had been staying at the lodge.

Over the next two days, Nielsen also killed the lodge’s owner, Julie Bullard, 65; her daughter Selby Bullard, 30; and her daughter’s friend Cindy Beatson, 43, to cover up the murder of Whitehurst. He used a chain saw, hacksaw and ax to cut the bodies in two, prosecutors said.

In between killing Whitehurst and the women, Nielsen worked two shifts as a cook in nearby Bethel.

Nielsen has offered little to explain what led to the killings. After his arrest, Nielsen told investigators he wanted to be a serial killer and had been thinking for five years about killing someone, according to a court document filed by prosecutors.

Brooke Bullard, whose stepmother and sister were killed, read a statement written by Selby Bullard’s 10-year-old son, Elliot, who now lives in California. In the statement, which Elliot titled “How my life changed and I was forever wounded,” the boy said he couldn’t understand the violence that took his mother’s and grandmother’s lives.

“They have all walked the stairway to heaven,” Bullard read. “At least there’s no violence up there.”

Nielsen’s father, Charles Nielsen, apologized for the pain his son has caused. He also asked the judge for compassion before he turned to his son and said: “I love you.”

Christian Nielsen’s mental health had been a focus of his defense, and he initially pleaded not guilty by reason of insanity. On Thursday, two forensic physiologists testified that he was not legally insane, but that he suffered from schizoid personality disorder, making it difficult for him to express emotions or remorse.

Dr. Charles Robinson said Nielsen’s motivation for the killings remains a mystery and the man himself is a puzzle even after talking with him nearly 20 times.

“I feel like I do not understand what has happened to him,” Robinson said.