LOWELL — Middlesex District Attorney Marian Ryan and the Lowell Police Department announced an arrest Monday afternoon in last week’s shooting death of 15-year-old Ahliana Dickey.

Trevor Bady, 21, of Tewksbury, was arrested without incident at a Peabody residence Monday afternoon, Ryan said during a press conference at the Lowell Police Department. Bady is facing charges of murder, armed home invasion, unlawful possession of a firearm, unlawful possession of ammunition, use of a firearm to commit a felony and discharge of a firearm within 500 feet of a building, said Ryan.

Bady is scheduled to be arraigned in Lowell District Court Tuesday morning.

Ryan said during the press conference that Dickey — who had just turned 15 on April 18 — was first noticed to be missing when she did not show up for her eighth grade graduation ceremony Friday morning.

“When she did not appear at that graduation, the family members who were awaiting her arrival were concerned and began attempting to locate her. That continued throughout much of Friday,” said Ryan.

Ryan said Dickey’s grandmother discovered Dickey at her Lawrence Street home at around 6 p.m. Friday. Dickey had visible gunshot wounds, Ryan said, and multiple shell casings were found at the scene.

From further investigation, Ryan said Bady was Dickey’s boyfriend, and Bady had been abusive to her leading up to her death.

“It was learned that Ahliana had confided in a number of people that Mr. Bady had been abusing her, and was threatening her as recently as the middle of last week,” Ryan said.

Thursday night into Friday, around midnight, Ryan said the Lowell Police received a call reporting some sort of fight taking place between a male and female outside on the street.

“The caller reported that she heard that female screaming, ‘Get off me. Get away from me. I don’t want to be with you anymore,’” said Ryan. “That caller further reported that they had heard gunshots. Police responded to the scene but did not locate anyone on the street after a search.”

Ryan said video surveillance was later found to have captured footage of Dickey and Bady on the street during the leadup to the shooting.

Bady took an Uber to and from Dickey’s home before and after the shooting, both times being the same driver, who later reported Bady as suspicious, Ryan said.

Ryan asked that Dickey’s family’s privacy be respected as they mourn their loss. She also emphasized the tragedy that has taken place, and said it was another tragic example of firearm violence in Middlesex County.

“What is important to remember about this incident is that Ahliana should have been finishing eighth grade on Friday,” Ryan said. “And also the same topic which I was here just about a week and a half ago speaking about, which is the prevalence and the use of guns in our community. This is at least the fifth individual to die by firearms in Middlesex County. That does not count those who have been shot and have survived.

“This time, it’s a 15-year-old girl,” Ryan continued. “We just cannot continue to countenance this kind of violence, the use of firearms, and the using a firearm in an argument and turning that from an argument to the tragic loss of life.”

Lowell Police Superintendent Greg Hudon thanked all of the departments and organizations that assisted in the investigation. Those included the police departments of Tewksbury, Nashua, Burlington, Peabody, Danvers and Saugus, as well as the Massachusetts State Police and Middlesex Sheriff’s Office.

“Most of all, I would like to thank the community for their assistance as detectives went, in some cases door-to-door, collecting information and video,” said Hudon.

Hudon called the shooting “an isolated incident,” and said there was no further danger to the public.

A GoFundMe was set up to help support Dickey’s family, which had raised more than $7,600 as of early Monday evening. A MealTrain account, a service that allows people to volunteer to make and donate meals to people in need of support, was also set up to help the family.