HARRISON, N.Y. (CBSNewYork/AP) — A retired White Plains police officer who apparently shot and killed his two teenage daughters and then himself left a suicide note, “indicating that the killings were premeditated,” police said Monday.

Police believe 52-year-old Glen Hochman shot and killed his daughters, 17-year-old Alissa and 13-year-old Deanna, and himself on Saturday. His wife, Anamarie, and a third, eldest daughter Samantha were not at home.

Harrison Police Chief Anthony Marraccini said Monday investigators found a five- to six-page typed suicide note with Hochman’s body in the garage of their home in Harrison. 17-year-old Alissa and 13-year-old Deanna apparently were asleep when they were shot in their own beds sometime after 2 a.m. Saturday, Marraccini said.

“Preliminary autopsy results revealed the single gunshot wounds to Alissa and Deanna were fatal, and there were no signs of a struggle, indicating that they were killed in their sleep,” Marraccini said.

As CBS2’s Matt Kozar reported, investigators believe Hochman wrote the note after killing his daughters.

Marraccini said that the handgun recovered near Hochman’s body, believed to be the weapon in the killings, belonged to Hochman. Three dogs had also been shot to death, Marraccini said.

Anamarie and the couple’s oldest daughter were away for the weekend. Mrs. Hochman was unable to reach anyone at the home.

Marraccini said that Hochman, a former White Plains Officer, had no known health or psychiatric problems. He said there also were no indications of alcohol or drug use.

On the day before the killings, his wife Anamarie had gone to police to report an argument over an $80 cellphone bill, but there was no indication of violence, Marraccini said.”Mrs. Hochman did not report any threats of physical violence and did not want the matter pursued,” he said. “Additionally, Mrs. Hochman reported that she only wanted to document this incident.”

Marraccini said investigators believe the report was made on the advice of a friend because the couple was considering separation.

Sources indicate to CBS2 the impeding separation was the motive for the killings.

The chief said his investigation had turned up that the couple had discussed “the possibility of separating due to marital issues” in mid-January. He would not say whether the discussion was considered a motive in the killings.

Police said there was no indication the Hochmans were having financial difficulties, but in a bizarre twist, one page of the suicide note contained instructions on what Mrs. Hochman should do to put their affairs in order, CBS2’s Lou Young reported.

Mrs. Hochman and Samantha were out of town on a planned visit to a Connecticut casino when the killings took place.

Marraccini said Mrs. Hochman became concerned Saturday when she was unable to get in touch with anyone at the home and sent Alissa’s boyfriend over to check on the house. That’s when he made the disturbing discovery and called police, Marraccini said.

“Alissa’s boyfriend discovered Mr. Hochman’s dead body within the garage,” Marraccini said.

White Plains Public Safety Commissioner David Chong said Hochman was a quiet, dedicated officer assigned to the city’s traffic division, retiring just last month after 22 years on the force.

“This absolutely abhorrent tragedy is so unexpected from this particular individual,” he said.

Last year, Hochman won the department’s life-saving award for keeping an unresponsive man alive until paramedics arrived.

Hochman suffered an Achilles’ injury in early May when he fell while helping a disabled motorist.

He had time off to recover according to his union lawyer, Warren Roth, who had known Hochman for more than 25 years, since both worked as EMTs with the Harrison ambulance corps.

He said Hochman sought a disability retirement because of the injury but had not been depressed over it as he was planning for retirement soon anyway.

“It’s just devastating to a lot of people,” Roth said.

According to Hochman’s wife, there were no prior domestic incident reports or a history of violence in connection with her husband, Marraccini said.

“During the course of the murder-suicide investigation and interviews with people who knew Mr. Hochman personally and professionally, there was no prior indication that Mr. Hochman would have committed this heinous act,” Marraccini said.

The police chief called the deaths a difficult struggle not only for the family, but for the officers who responded to the scene and the community as a whole.

“I’m not sure anyone can understand how a person kills his children,” Marraccini told reporters, including WCBS 880’s Sean Adams and 1010 WINS’ Sonia Rincon.

“It’s difficult, especially when you see two young girls — their life’s been ripped away, so brutally murdered,” he added. “You can’t get any rationale for that.”

Harrison High School, where Alissa was a senior, opened its campus on Sunday for grief counseling. Deanna was a student at the Windward School in White Plains.

Counselors were also at the girls’ schools on Monday, where a sign out a front displays a single candle of tribute.

“I was shocked,” Harrison High School student Ben Rubin told CBS2’s Janelle Burrell. “Just terrible for something like this to happen.”

The Hochman family name is on a plaque near the entrance at the Windward School.

As CBS2’s Matt Kozar reported, sources say Glen Hochman is the son of Dr. Judith Hochman, the former head of the school.

“This is certainly not the police officers that I know,” David Chong, White Plains Public Safety Commissioner, said.

Chong, Hochman’s former boss, said he was an exemplary officer.

“This absolutely abhorrent tragedy is so unexpected from this particular individual,” Chong said.

On the Harrison Central School District website, Superintendent Louis N. Wool said the district mourned the deaths of two girls “both lost to incomprehensible tragedy.”

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