The man arrested in connection with a homicide this week in a Brewers Hill apartment complex was found by Baltimore County Police at a residence in Owings Mills where he was armed with an AR-15 rifle and clearly upset, according to charging documents.

He later told the county officers that he had “shot his girlfriend Amy,” Baltimore Police wrote.

That’s when a city police officer entered the pair’s Brewers Hill apartment early Monday and found Amy Armstrong, 28, shot to death near a bullet casing. The suspect, Gabriel Gomez-Fiorenza, who told police he was her boyfriend, was taken into custody and faces charges of first-degree murder and assault.

The charging documents, written by Baltimore Police, state that Gomez-Fiorenza waived his Miranda rights and told detectives that he got in a verbal argument with Armstrong on Sunday night around 11 p.m. When the argument ended, she went into their bedroom and he retrieved an AR-15 assault rifle from under their bed.

He told police he put the weapon on the kitchen counter and “intentionally chambered a round into the gun.” When he did so, Armstrong came out. Gomez-Fiorenza told police he “was going to shoot himself,” but that she intervened and attempted to get the gun away from him.

In the ensuing struggle, which took place with “his finger on the trigger,” she was shot in the head and collapsed, according to Gomez-Fiorenza and police.

“The defendant stated he then went over to the victim and called her name, and she didn’t respond,” police wrote. “The defendant admitted he observed the gunshot wound to his girlfriend/victim’s head and did not attempt to render aid to her or call for medical assistance.”

He told police he then went to his vehicle and drove to Owings Mills, where his family lives. He was found there in Baltimore County with an AR-15.

Baltimore County Police contacted Baltimore Police earlier on Monday morning while dealing with Gomez-Fiorenza in a yard where he was threatening to kill himself.

City police were initially dispatched to their apartment building because county officers thought his girlfriend might be able to “provide insight as to what was troubling him.” The city officer got no answer at the door.

A little over two hours later, the officer returned to the building and entered the apartment, after Baltimore County took him into custody and he “indicated to them that he shot his girlfriend Amy inside the location.”

The shooting took place in the 3700 block of Toone Street, according to police. Police said Tuesday that investigators “quickly learned” the suspect “shot and killed” the victim inside their apartment “following a domestic related dispute.” A news release on the homicide arrest said he was taken into custody in Baltimore County and subsequently transported to the Central Booking Intake Facility, where he was charged with first- and second-degree murder and first- and second-degree assault.

The charging documents in the case were provided to The Baltimore Sun by the State’s Attorney’s Office. The criminal case does not yet appear in an online courts database; it’s not clear whether Gomez-Fiorenza has an attorney.

Someone who answered the phone at The Porter apartment building, located in the block provided by police, directed a reporter to a media relations company, which did not immediately respond to a request for comment sent Tuesday.

Family members of Armstrong could not immediately be reached for comment.

Brant Fisher, president of Brewers Hill Neighbors, the local community association, called the shooting an “aberration” for the neighborhood, calling it a “small, tight-knit community”

“The community looks out for each other and supports one another. It’s a great place for young and old people to live and have their children here. These things, they’re not an everyday occurrence here for us,” Fisher said, adding the incident shouldn’t “take away from the charm of this neighborhood and what it’s all about.”

A Baltimore Police crime map says there has been one homicide, Armstrong’s, so far this year in Brewers Hill. It lists four aggravated assaults, five robberies and three commerical robberies since the start of 2024, along with 27 larcenies, 20 larcenies from vehicles, 19 auto thefts and five burglaries.

Baltimore is seeing fewer homicides and shootings this year compared to last. There have been 166 homicides, compared to 222 in the same period in 2023, and 344 nonfatal shootings, compared to 538 in the same period last year, according to police figures sent Tuesday morning.

A website for Mr. Mixology, a bartending services company, lists a Gabe Fiorenza and Amy Armstrong on its “who we are” page.

It identifies Fiorenza as a bartender for his family’s seafood restaurant in Baltimore City for the past eight years, saying he was “inspired to start” the company “to extend his knowledge and expertise to the wedding and events industry.”

Armstrong is described as someone with experience in the sales and marketing industry, who works with wedding vendors to help grow their businesses.

There was no answer on Tuesday afternoon for the phone number listed for the business.

Baltimore Sun reporter Amanda Yeager contributed to this article.