NORWALK, Conn. (CBSNewYork/AP) — A man fatally shot his 33-year-old daughter before turning the gun on himself and taking his own life, police in Connecticut said.

Melissa Wilkinson worked two jobs, and authorities say her co-workers became concerned when she didn’t show up for work Sunday night.

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They went to her apartment and spotted her through a window collapsed and bleeding, CBS2’s Ali Bauman reported. Her co-workers forced their way into the apartment just after midnight and saw her father on the couch next to her body mumbling to himself and holding a gun.

The co-workers left and called 911, and a standoff ensued.

Armed and incoherent, 55-year-old Mark Wilkinson stayed in his daughter’s apartment for hours while police tried to persuade him to come out.

“It was a variety of ways we tried to contact him,” Norwalk Police Lt. Terry Blake Said. “Via phone, window, loudspeaker, and he did not return communication to us.”

Officers later heard a single gunshot and police forced their way into the apartment where they found the bodies of the father and daughter, shot in the head.

The deaths remain under investigation.

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Melissa’s mother Karen told CBS2 Mark had been living with his daughter for two years and that they had been fighting, but she cannot imagine why he would kill her.

“Right now I really don’t know, I really don’t know,” she said. “She was always positive and she had her life together she had a good job.”

Co-workers described Melissa as a great employee with a smile that could light up a room.

Police said they had not received any complaints of arguing from the apartment and there was no record of domestic violence.

Some residents of the neighborhood were evacuated while some were told to stay in their homes during the incident.

Anyone with information is asked to call the Norwalk Police Tip Line at 203-854-3111.

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(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)