An approximate timeline of the Dec. 20 events surrounding the deaths of officers Rafael Ramos and Wenjian Liu, as detailed by law enforcement and government officials:
5:50 a.m. - Shaneka Nicole Thompson, 29, is shot in the stomach by her ex-boyfriend in Owings Mills, Maryland, leaving her in critical but stable condition. She is expected to survive.
6:05 a.m. - Ismaaiyl Brinsley, 28, calls Thompson's mother and tells her he shot her daughter by accident and he hopes she lives.
10:50 a.m. - Brinsley arrives at Manhattan's Port Authority after a lengthy bus ride. He carries with him the cellphone he stole from Thompson and the 9mm handgun he used to shoot her.
12:20 p.m. - Brinsley uses Thompson's phone to post an ominous message on Instagram, saying "I'm Putting Wings On Pigs Today. They Take 1 Of Ours....... Let's Take 2 of Theirs."
12:50 p.m. - After traveling to Brooklyn by subway, Brinsley ditches Thompson's cell phone near the Atlantic Yards complex.
1:30 p.m. - Thompson's mother calls Baltimore police to warn them about the Instagram posting. She says she believes Brinsley has ties to a church on Church Avenue in Brooklyn.
1:45 p.m. -- Baltimore police prepare a "wanted" flyer to distribute to law enforcement agencies, including the NYPD.
2:10 p.m. - Baltimore police call the 70th precinct, near the Brooklyn church, to warn them. A Baltimore detective speaks with an NYPD officer for about half an hour to review the details. Police said the NYPD officer reviewed the Instagram posts and photos of Brinsley during the call and asked for the "wanted" flyer to be faxed to the 70th precinct..
2:46 p.m. - Baltimore police fax the "wanted" flyer, which contained the same photos seen in the Instagram posts, to the 70th precinct. The precinct receives it a short time later.
2:48 p.m. - Brinsley approaches Ramos' and Liu's patrol car, takes a shooter's stance, and shoots four bullets through the passenger-side front window, striking both officers in the head. Under pursuit by police, he runs into a nearby subway station and fatally shoots himself in front of at least 10 witnesses.