'I Did the Shooting': Orlando Nightclub Massacre 911 Calls Revealed

— -- After opening fire on a group of innocent people in a gay nightclub in Orlando, Florida, eventually killing dozens, gunman Omar Mateen called police to tell them who he was and what he'd done.

"This is Mateen. I want to let you know I'm in Orlando and I did the shooting," Mateen says in one of three calls to 911 in the early morning hours of June 12, transcripts of which were released today by the city of Orlando.

In the calls Mateen pledges allegiance to the Syria-based terror group ISIS and says he "feel[s] the pain of the people getting killed in Syria and Iraq and all over the Muslim..." but doesn't finish the sentence. When the police officer on the other end of the line asks if he's done something about it, Mateen replies, "Yes I have... You already know what I did."

Later in the call Mateen refers to his "homeboy" Tamerlan Tsarnaev, one of the 2013 Boston Marathon bombers, and calls him a "soldier of God."

The three calls between Mateen and the police negotiator unfold over a period of 50 minutes, beginning with the first call at 2:35 a.m. In their last conversation at 3:25 a.m., the negotiator tells Mateen to come outside without any weapons, but Mateen doesn't reply.

Mateen, a New York native of Afghan descent, killed 49 people in his rampage before being gunned down by police. Mateen had been investigated previously by the FBI after he made "inflammatory" comments to co-workers in 2013, but he was determined not to be a threat.