A state trooper shot and killed his ex-girlfriend, a Newington police officer, then turned the gun on himself in a murder-suicide Monday evening.

Ciara McDermott, 30, was found dead around 6:30 p.m. in her house at 348 Ridgewood Road. Sources said she was killed by state Trooper Victor Diaz, who was scheduled to turn himself in to West Hartford police earlier Monday on charges he harassed McDermott.

Diaz, 37, called his attorney, Jeffrey Ment, and left him a message Monday saying, "There's been a change of plans," sources said. He then went to McDermott's home and killed her, said sources.

Diaz's body was discovered about two hours later, after police called off a manhunt for Diaz and re-entered the home, sources said. It was not clear where Diaz's body was found in the house or why it wasn't found when police originally responded.

Law enforcement sources said McDermott's body was discovered by a West Hartford police officer who she had started dating recently.

Diaz had been serving a 60-day suspension from his job, the most serious penalty short of firing, following his arrest in March on a DUI charge. He had been ordered to turn his gun in to state police. It was not clear what weapon he used in the shooting on Monday. Diaz had been arrested by Cromwell police after a chase last March.

Diaz's car was found a short distance from McDermott's home, in Wolcott Park off New Britain Avenue. Police believe that Diaz parked the car away from the house so he wouldn't be spotted and then walked to McDermott's house.

McDermott was the school resource officer in Newington. She was just at Newington High School Monday to provide grief counseling to students mourning the death of Brendan Horan, 17, a high school senior who died Friday night in an all-terrain vehicle accident. Students gathered late Monday to hold a vigil to remember Horan, but it also turned into a memorial for McDermott.

McDermott had been with the department since August 1998. Her father, Peter McDermott, is a former West Hartford police officer and retired Windsor police captain who now works at the Municipal Police Training Academy.

Late Monday, a Newington school bus dropped off about 40 officers, some in uniform, some not. They walked quietly and slowly in two straight lines toward McDermott's home, then stood at attention and saluted the tan Colonial house. The officers afterward walked quietly back to the bus.

The incident marked the second time in the past year that a Newington police officer has died at the hands of a gunman who then shot and killed himself.

Last December, Peter Lavery, 47, a father of two, was fatally shot while answering a domestic complaint. The veteran officer and Berlin resident was shot at a Mountain View Drive home by Bruce A. Carrier, who committed suicide during a standoff with police.

On Monday, police initially had believed that Diaz was at large in the area of Ridgewood Road near Westfarms mall in the southwest corner of town. A state police helicopter was brought in to assist in the manhunt.

Police closed off several area roads and locked down Conard High School as a precaution. About 200 to 300 people were at the school for a pre-production meeting for the play "Annie" at Sedgwick Middle School.

Local and state police also waited for Diaz at what was believed to be his home on Sheffield Drive in Windsor.

Sources familiar with the case said Diaz, who worked at the Troop H barracks in Hartford, recently had learned that McDermott was dating another officer.

McDermott had complained to state and local police that Diaz was harassing her by making threatening calls.

Sources said West Hartford police had an arrest warrant charging Diaz with illegally accessing state police records to run a license plate of a car he saw in McDermott's driveway. Ment, Diaz's lawyer, would not comment when reached late Monday.

Police evacuated Newington Town Hall as a security precaution, and two local board meetings were canceled. Newington Town Manager Paul Fetherston was grim and clearly upset that a second police officer has been killed in less than a year.