Ismaaiyl Brinsley in a photo provided by the NYPD on...

Ismaaiyl Brinsley in a photo provided by the NYPD on Sunday, December 21, 2014. Brinsley allegedly shot and killed NYPD Officers Wenjian Liu, 32, and Rafael Ramos, 40, as they sat in their patrol car near Myrtle and Tompkins avenues in Brooklyn's Bedford-Stuyvesant section. Credit: Charles Eckert

Ismaaiyl Brinsley was a troubled youth from Brooklyn with a history of petty crimes, time spent in prison and a mother who told police she was afraid of him.

His life ended in violence Saturday after he shot an ex-girlfriend, killed two NYPD officers and then turned the gun on himself.

Brinsley, 28, had a criminal record that included 19 arrests -- 15 in Georgia and four in Ohio for a variety of crimes, including misdemeanor assault; shoplifting; grand larceny and gun possession, police said. He served a 2-year prison term in Georgia from August 2011 to July 2013 for criminal possession of a weapon.

Police and Brinsley's family have been trying to understand what drove him to first go to Baltimore County, where police say he shot former girlfriend Shaneka Nicole Thompson, 29, and then travel to Brooklyn, where he fired four rounds into a police patrol car, killing Officers Rafael Ramos and Wenjian Liu.

His social media presence indicates anger against police after two high-profile cases in which black men were killed by white officers.

Brinsley's mother told police he "had a very troubled childhood and was often violent," NYPD Chief of Detectives Robert Boyce said at a news conference in Manhattan late Sunday.

His mother also told police Brinsley tried to hang himself one year ago. She told police she suspected he had "undiagnosed mental health issues."

Brinsley was born in Brooklyn to a Muslim family, and relatives said he "never expressed any radicalization at all," Boyce said.

His mother still lives in Brooklyn and his father lives in New Jersey, where Brinsley attended high school. He had two sisters, and he was estranged from both.

At a Georgia residence listed as a former address for Brinsley, a woman who gave her name as Anastasia Desmond said Sunday she is a cousin of Brinsley's and his family was "struggling to understand" the killings.

"He had problems with the law, but . . . I never believed he could do what they say he did," Desmond said. "I saw his picture on the news and I thought, 'Oh my God, he actually did this.' "

She added, "He wasn't a bad person, but he did bad things."

Asked if Brinsley had anti-police beliefs, she said: "I think yesterday speaks for itself."

"I think he had problems in his life he blamed on police and the system," she said.

Brinsley's social media presence in the weeks leading up to the shootings held clues to his state of mind. Police were reviewing his online activity and seeking a warrant to access photos and videos on his cellphone.

"What we're seeing right now is anger against the government," Boyce said. "There is one [Instagram post] where he burned the flag and made some statements. There's others that talk of anger against police. He specifically mentions Michael Brown and Eric Garner."

She said Brinsley expressed "self-despair" and "anger at himself for where his life is now."

Police were unsure of where he was living. He last address was listed as the home of his estranged sisters in Union City, Georgia, but officials said he hadn't lived there in two years.

"Because he had problems, he was going back and forth to his relatives in Georgia," he said.

Boyce said Brinsley was estranged from his child in Brooklyn and the child's mother.

Major Case Squad detectives are seeking a full statement from the ex-girlfriend.

Brinsley appeared to have one moment of remorse as he spoke on the phone with the woman's mother, telling her "he shot her [daughter] by accident and that he hopes she lives," Boyce said.

With Nicole Fuller and Anthony M. DeStefano

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