WESTBROOK — As police continue to piece together details of Saturday’s murder-suicide in Westbrook, friends of shooting victim Matthew Rairdon reacted with shock Sunday and described him as an ambitious young man who was passionate about being a nurse.

Rairdon, 22, a Westbrook native, was shot to death early Saturday by Patrick Milliner of South Portland, according to Maine State Police. Milliner then turned the .40-caliber Glock pistol on himself. The murder-suicide occurred at Rairdon’s downtown apartment at 318A Main St., and the weapon was purchased the night before, state police said.

Milliner’s public Facebook page indicated the 30-year-old had recently moved from Colorado to Maine. State police said the two had a romantic relationship that had recently ended.

Westbrook Mayor Colleen Hilton said the Rairdons are well-known in the community, and she personally has known the family for many years.

“It’s a senseless tragedy,” Hilton said Sunday. “A great kid, a tragic loss. Our community is in mourning today. We’ll all be there for them.”

Rairdon’s father, Gary Rairdon, won election in November to the Westbrook City Council, his first attempt at an elected office. Attempts to reach the family Sunday were unsuccessful.

Domestic violence in same-sex relationships is rare but not unheard of, according to anti-domestic violence advocates in the state. Of roughly 2,500 people who called a Portland domestic violence help line in 2012, about 160 were men, half of whom are thought to be gay, said Lois Reckitt, executive director at the Portland-based Family Crisis Services. She said Saturday’s killing is the first intimate-partner homicide in Cumberland County since July 2011.

“What we have to be concerned about is that the LGBT community is not as comfortable in contacting domestic violence organizations as they could be,” Reckitt said. “I don’t think it comes out of the blue. It’s not like this guy or any guy just all of a sudden snaps. There’s some kind of pattern in the relationship that to a trained eye might be discernible as a warning sign.”

Rairdon, a 2009 graduate of Westbrook High School, was also a graduate of Saint Joseph’s College in Standish and had recently started working as an emergency room nurse at Mercy Hospital in Portland.

Rairdon also enjoyed acting while he was in high school, according to family friends, and he won a high school drama award.

Mark Munson, who worked with Rairdon on theater productions for Reindeer Theatre in Westbrook, said Rairdon immersed himself in his acting roles.

“Even then, as a young person in high school, he had these qualities where he was open, friendly and generous,” Munson said. “What you saw is what you got, in the best way.”

Munson said when he heard Rairdon wanted to become a nurse, he knew that he would be successful based on his work ethic and caring attitude.

“We knew he was truly in his element. He dedicated his life to helping people, and he had a passion for nursing,” said Munson, who would sometimes run into Rairdon when Rairdon worked at Mister Bagel in Westbrook. “It is beyond injustice that he was killed.”

Louis Philippe, director at Reindeer Theatre, said Rairdon’s death was “a shock.”

“He had a maturity level that was way beyond his years,” Munson said. “He was clearly a role model, and he worked very well with every other cast member.”

Both Rairdon and Milliner had likely worked on the Equality Maine campaign, the successful 2012 effort to permit same-sex marriage in the state, according to Milliner’s Facebook posts.

Milliner was a new correctional guard at the Maine Correctional Facility in Windham, state police said. Milliner’s Facebook page indicated he was excited about the move from Colorado.

“Yea(h), I’m not a fan of lobster, and I root against the (Boston) Bruins and Red Sox, but I do love blueberries and I really love me some New England Patriots. I visited and worked in Maine for the first time in 2009. I fell in love with its natural beauty, its people, and I knew I would make it there someday. I am SO excited!” Milliner wrote in a June 4 Facebook post.

Milliner also wrote on Sept. 2: “One of my favorite memories in Maine so far was watching family videos with his family today. Still smiling — with Matt Rairdon.”

A state police spokesman said the state medical examiner’s office was performing autopsies Sunday on both men, and more details about the crime would become known this week.

Although authorities did not pinpoint when Rairdon and Milliner split up, the period after a breakup is considered the most dangerous, especially if one partner has access to or recently purchased a gun, said Julia Colpitts, executive director of the Maine Coalition to End Domestic Violence. In the most recent review of domestic violence homicides in Maine, spanning 2010 to 2011, nine of the 13 perpetrators examined exhibited suicidal tendencies before they acted, with six killing themselves after killing an intimate partner.

Both Colpitts and Reckitt lauded police in their respectful handling of the case in light of the same-sex nature of the relationship.

“There was no snickering,” Reckitt said. “I’ve been doing this work for 35 years, and it hasn’t always been this way.”

Joe Lawlor can be contacted at 791-6376 or at:jlawlor@pressherald.comTwitter: @joelawlorphMatt Byrne can be contacted at 791-6303 or at: mbyrne@pressherald.com