This story was reported by Globe correspondents Emily Williams and J.D. Capelouto and staff reporters Michael Levenson, Emily Sweeney, and John R. Ellement. It was written by Levenson.

WEYMOUTH — The 20-year-old man accused of shooting and killing a Weymouth police officer and a woman in her home this weekend has a history of drug use, instability, and run-ins with the law, according to friends and court records.
Emanuel A. Lopes is accused of shooting Officer Michael C. Chesna about 10 times with the officer’s own gun and then firing three rounds into the sliding glass doors of Vera Adams’s Torrey Street home, fatally wounding the 77-year-old widow, authorities alleged Monday.
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When police captured Lopes, he was still holding Chesna’s pistol, and evidence suggests he had fired all 15 or 16 bullets it held, police wrote in a report.
Friends and court records described Lopes as a troubled man who attempted suicide when he was a sophomore at Weymouth High School, according to a childhood friend.
Nick Donovan, who has remained close with the suspect, said that Lopes was in the waiting room of the guidance counselor’s office when he grabbed a pair of dull scissors and repeatedly stabbed himself in the neck.
“He tried to kill himself,’’ Donovan said, adding that Lopes had a “troubled” relationship with his mother and his stepfather. Lopes lived at Donovan’s house for several months in 2017 after a series of arguments at home.
Relatives of Lopes could not be reached.
Will Perron, who was a year ahead of Lopes in middle and high school, said Lopes was “unpredictable” — known to be aggressive and get into fights.
During middle school, Perron said, Lopes hit him over the head with a textbook and fought him.
“It’s always been a short-fuse situation,” he said. “He’s never had the ability to reel in that temper.”
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Lopes was arrested by Weymouth police at least twice before, according to court records.
In September, he was arrested after he allegedly threw a rock through the window of a house on Lee Street, where residents had ordered him to leave, according to a police report.
In October, Lopes was charged by Weymouth police with selling cocaine to minors and resisting arrest.
“We have fought with him before,’’ Officer Edward Hancock wrote in an arrest report.
“[Lopes’s] mother was spoken to via the phone,’’ Hancock wrote. “She stated that she was going to go to Quincy District Court and [involuntarily committing] [Lopes] first thing in the morning, and was planning an intervention before this incident occurred.”
Lopes was involuntary committed to a treatment center to determine whether he had an alcohol or substance use disorder, according to court records. Lopes remained in custody until Nov. 8, 2017, when a friend posted $500 cash bail. But by Nov. 25, Lopes was off the streets and was receiving “clinical stabilization services” as an inpatient at the High Point Treatment Center, according to court records. He remained there at least until mid-December, but his release date was not immediately clear.
The ferocity of the Sunday morning attack was outlined in a police report filed in Quincy District Court, where Lopes is expected to be arraigned on two counts of murder. The suspect, who was shot in the leg by a Weymouth officer as he ran away from the scene, was not healthy enough to face a judge Monday and is slated to be arraigned Tuesday.
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According to the police report, the violence erupted around 7:30 a.m. Sunday in a normally quiet neighborhood near South Shore Hospital, where Lopes had crashed a car and then fled from police.
Chesna was sent to investigate. Chesna found Lopes on Burton Terrace, where he was throwing decorative stones into the windows of a home owned by someone who did not know Lopes, police wrote in the report.

Lopes, who is 6 foot 3 and weighs 175 pounds, threw a large rock at Chesna, who was standing in the middle of the street about 10 to 12 feet away, police said. The rock struck Chesna in the head, causing him to fall to the ground and drop his gun, the report said.
At that point, police say, Lopes picked up Chesna’s gun, stood over Chesna, and fired about five times into Chesna’s head and five times into his legs and torso, police wrote.
When Weymouth Officer Sean Murphy arrived, he saw Lopes standing over Chesna with the gun pointed toward the officer, the report said. Murphy fired at least one round through his windshield, wounding Lopes in one leg, police wrote.
Chesna, 42, and the father of two children, ages 9 and 4, was pronounced dead at South Shore Hospital.
Lopes was able to run off after being shot by police. While being pursued, he fired three shots into the home of Adams, who was struck and killed, police wrote.
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On the day after the shooting, friends described Adams as a shy retiree who loved reading mystery and crime novels.
“She was just a wonderful, wonderful person — do anything for you,” said Sandra Boucher, 76, the sister of Adams’s late husband, Donald Adams.
Residents and officials grieved the deaths of Adams and rallied to support Chesna’s family.
Chesna, an Army sergeant, served in Iraq from September 2007 to October 2008 and in Afghanistan from April 2010 to April 2011. Among other decorations, he was awarded the Bronze Star and the Army Commendation Medal, according to the Pentagon.
On Monday, mourners lined the route between Boston and Weymouth as Chesna’s body was escorted by his fellow officers from the state medical examiner’s office to the McDonald Keohane Funeral Home.
Some people standing on the sidewalk put a hand over their hearts. A few carried small American flags.
Matthew Menz, a Weymouth firefighter, came with his two daughters, ages 2 and 4 months, to pay his respects. He had met Chesna on duty, he said.
“To see this is just so sad,” Menz said. “I don’t even know how to get it into words.”
Chesna’s father-in-law, Francis Doran, 78, of Marshfield, said Sunday he was worried for Chesna’s two young children.
“I don’t know what’s going to happen to Mike and Cindy’s boy and girl. I don’t know how much a 4-year-old understands, how much a 9-year-old understands,” he said in a telephone interview. “They absolutely loved their father.”
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Weymouth Mayor Robert L. Hedlund praised the generosity of residents and business owners who have pledged donations to help Chesna’s family.
“There’s been a huge outpouring of financial assistance for the family coming from all directions,” he said.
The mayor also expressed horror that Adams was “senselessly murdered” while sitting in her home.
Globe correspondent Jeremy C. Fox and Jerome Campbell of the Globe staff contributed to this story. Michael Levenson can be reached at mlevenson@globe.com. Follow him on Twitter @mlevenson. Emily Sweeney can be reached at esweeney@globe.com. Follow her on Twitter @emilysweeney. John R. Ellement can be reached atellement@globe.com. Follow him on Twitter @JREbosglobe.