December 21, 2014 5:02 PM EST
M oments before he ambushed and killed two New York police officers, gunman Ismaaiyl Brinsley told passersby to follow him on Instagram and then said, “Watch what I’m going to do,” investigators said Sunday.
The disclosure came as police sketched a timeline of Brinsley’s activities in the hours before he shot and killed Officers Wenjian Liu and Rafael Ramos in Brooklyn on Saturday. Brinsley later killed himself. Investigators said Brinsley, 28, shot his ex-girlfriend at her Baltimore apartment after an argument, then took a bus to New York.
On social media accounts, he occasionally ranted against police and government, investigators said.
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Witness the Aftermath of Police Shooting in Brooklyn The skyline of Manhattan is seen in the background as investigators work at the scene where two NYPD officers were shot in the Brooklyn borough of New York City on Dec. 20, 2014 John Minchillo—AP Police are pictured at the scene of a shooting where two New York Police officers were shot dead in the Brooklyn borough of New York City on Dec. 20, 2014. Carlo Allegri—Reuters Police are pictured at the scene of a shooting where two New York Police officers were shot dead in the Brooklyn borough of New York City on Dec. 20, 2014. John Taggart—EPA A police officer wipes tears away from his face as he walks away from the scene of a shooting where two New York Police officers were shot dead in the Brooklyn borough of New York City on Dec. 20, 2014. Carlo Allegri—Reuters Police pay their respect outside Woodhull Hospital as two Police ambulances carrying the bodies of two murdered officers head to Bellevue Hospital in New York City, Dec. 20, 2014. Paul Martinka—Polaris A man leaves flowers at an impromptu memorial near the site where two police officers were killed the day before in the Brooklyn borough of New York City on Dec. 21, 2014. Seth Wenig—AP New York City police officer Darren Cox, right, accompanied by fellow officers, leaves flowers at a memorial in the Brooklyn borough of New York City on Dec. 21, 2014. Mark Lennihan—AP Donna Salvaggio (L) and a woman who gave her name as Reverend Jordan hug at a makeshift memorial at the site where two police officers were shot in the Brooklyn borough of New York City, Dec. 21, 2014. Carlo Allegri—Reuters A man takes part in a prayer vigil at the site where two police officers were fatally shot in the Brooklyn borough of New York City, Dec. 21, 2014. Carlo Allegri—Reuters Mourners take part in a prayer vigil at the site where two police officers were fatally shot in the Brooklyn borough of New York City, Dec. 21, 2014. Stephanie Keith—Reuters New York Police Department officers Mark Cava, left, and Jason Muller participate in a moment of silence for two slain NYPD officers before an NBA basketball game between the Brooklyn Nets and the Detroit Pistons in New York City on Dec. 21, 2014. Jason DeCrow—AP New York Police Department officer Jason Muller salutes during the national anthem after participating in a moment of silence for two slain NYPD officers before an NBA basketball game between the Brooklyn Nets and the Detroit Pistons in New York City on Dec. 21, 2014. Jason DeCrow—AP A woman recites from a Bible while standing over a makeshift memorial during a prayer vigil at the site where two New York Police Department (NYPD) officers were fatally shot in the Brooklyn borough of New York City, Dec. 21, 2014. Stephanie Keith—Reuters Mourners take part in a prayer vigil at the site where two police officers were fatally shot in the Brooklyn borough of New York City, Dec. 21, 2014. Stephen Shames—Polaris More Must-Reads from TIME Donald Trump Is TIME's 2024 Person of the Year Why We Chose Trump as Person of the Year Is Intermittent Fasting Good or Bad for You? The 100 Must-Read Books of 2024 The 20 Best Christmas TV Episodes Column: If Optimism Feels Ridiculous Now, Try Hope The Future of Climate Action Is Trade Policy Merle Bombardieri Is Helping People Make the Baby Decision