Moments before he fatally shot two police officers at point-blank range, Ismaaiyl Brinsley told a couple of passersby: "Watch what I'm going to do."
NYPD Chief of Detectives Robert Boyce mentioned that encounter Sunday during a news briefing focused on the timeline in the slayings of Officers Rafael Ramos and Wenjian Liu as they sat in their squad car on a Bedford Styvesant street.
Brinsley happened upon two young men prior to the 2:47 p.m. attack on Saturday, Boyce said. He asked whether they had any gang affiliation, told them to follow him on Instagram and then suggested they watch what he planned to do next, the chief said.
Brinsley proceeded to walk up to a parked patrol car and fire four shots into the passenger side window, killing both officers.
He fled the scene and was spotted by two Consolidate Edison workers who chased him in their truck and called police. Brinsley ran into a nearby subway station and shot himself in the head. There were 10 eyewitnesses to his suicide, Boyce said.
Investigators believe the gunman posted a threatening message on a social media account before the shooting, according to a law enforcement source. "They take 1 of ours, let's take 2 of theirs," said the post on Instagram, which was accompanied by a photo of a silver handgun.
"I'm putting wings on pigs today," the post added.
Brinsley shot and injured his ex-girlfriend at about 5:30 a.m. Saturday in Baltimore with that same 9 mm weapon he used to kill the officers, Boyce said.
Brinsley was trying to get back together with his former girlfriend, Shaneka Nicole Thompson, but "she did not want to have anything to do with her," Boyce said. Thompson, 29, remained in critical but stable condition Sunday after being shot in the stomach, Baltimore County police said. She was expected to survive.
Thompson's mother warned Baltimore police about the Instagram posting around 1:30 p.m. and said she thought Brinsley had ties to a church along Church Avenue in Brooklyn, said a police source briefed on the situation. Baltimore police called New York's 70th precinct just after 2 p.m., and also faxed a wanted poster for Brinsley to New York. Baltimore police said they faxed the poster at about 2:10 p.m., but Bratton said it was sent at about 2:45 p.m. There was no immediate explanation for the discrepancy.
The NYPD received the fax just moments before the attack on Ramos and Liu - a "tragic irony," Bratton said Saturday.
Criminal records show Brinsley has a history of arrests on various charges in Georgia, including robbery, shoplifting, carrying a concealed weapon, disorderly conduct and obstruction of a law enforcement officer.
"All his trouble appears to be in the South," Boyce said.
Brinsley's mother and sister told the NYPD that he was a violent person and that they were afraid of him. Police said Brinsley had an 11-month-old baby with a girlfriend who lived on Nostrand Avenue in Brooklyn, and his mother lives in Crown Heights.
Boyce said investigators found no evidence that Brinsley was a gang member or made any extremist religious statements.
"I have no reports of mental history," he added. "He may have been on meds later on in his life."
During a Saturday news conference, Mayor Bill de Blasio called the shootings a "particularly despicable act" and asked residents to pray for the officers and their families.
"Our entire city was attacked by this heinous individual," he said. "Our city is in mourning. Our hearts are heavy."
The killings come as the NYPD faces public outrage and an at times tense relationship with City Hall in the wake of incidents including the chokehold death of Eric Garner, a black man who died when white police officers attempted to arrest him for selling loose, untaxed cigarettes. A grand jury decided on Dec. 3 not to indict any officer in Garner's death, sparking protests in New York and other cities nationwide. Four people have been arrested in connection with attacks on police at a protest march on the Brooklyn Bridge.
At Woodhull Medical Center, following the deaths of Ramos and Liu, a number of officers turned their backs on de Blasio as he walked through the hallway.
Patrolmen's Benevolent Association President Patrick Lynch linked the killings to violence against the NYPD during the recent protests over Garner's death and to what he said was the mayor's lack of support for the department.
"There's blood on many hands tonight," Lynch said, adding: "That blood on the hands starts on the steps of City Hall in the office of the mayor."
De Blasio responded that Lynch's remarks amounted to "irresponsible, overheated rhetoric that angers and divides people."
President Barack Obama was among many officials nationwide to condemn the violence.
"I ask people to reject violence and words that harm, and turn to words that heal - prayer, patient dialogue, and sympathy for the friends and family of the fallen," he said in a statement
Gwen Carr, Garner's mother, echoed the call for peace.
"Anyone who's standing with us, we want you to not use Eric Garner's name for violence because we are not about that," she told reporters.
"We reject any kind of violence directed toward members of law enforcement. It cannot be tolerated. We must work together to bring peace to our communities," said a statement from the family of Michael Brown, the unarmed black teenager who was shot and killed by a white officer in Ferguson, Missouri. In that case, too, the officer was not indicted.
The Rev. Al Sharpton, who has spearheaded protests, said on Sunday that he had received threatening phone messages in the wake of the shootings, and that he planned to turn them over to the FBI.
Police departments and union leaders around the country are warning the rank and file to wear bulletproof vests and avoid making inflammatory posts on social media, The Associated Press reported.