Mateen, who killed 49 and wounded 53 in the June 12 shooting at a gay nightclub, spoke to 911 dispatchers several times during the massacre.
The transcripts of those calls, however, do not include Mateen's oath of loyalty to ISIS or any other religious justification for the attack.
Here is what the FBI released:
Investigative Update Regarding Pulse Nightclub Shooting
ORLANDO - In order to provide an update on the progress of the investigation into the Pulse nightclub shooting, the FBI is releasing an excerpt from the timeline of events inside the Pulse nightclub during the early morning hours of Sunday, June 12, 2016. Out of respect for the victims of this horrific tragedy, law enforcement will not be releasing audio of the shooter's 911 calls at this time,nor will law enforcement be releasing audio or transcripts of the calls made by victims at the Pulse nightclub during the incident. Furthermore, the name of the shooter and that of the person/group to whom he pledged allegiance are omitted.
The following is based on Orlando Police Department (OPD) radio communication (times are approximate):
2:02 a.m.: OPD call transmitted multiple shots fired at Pulse nightclub.
2:04a.m.: Additional OPD officers arrived on scene.
2:08 a.m.: Officers from various law enforcement agencies made entrance to Pulse and engaged the shooter.
2:18 a.m.: OPD S.W.A.T. (Special Weapons & Tactics) initiated a full call-out.
2:35 a.m.: Shooter contacted a 911 operator from inside Pulse. The call lasted approximately 50 seconds, the details of which are set out below:
Orlando Police Dispatcher (OD)
OD: Emergency 911, this is being recorded.
OM: In the name of God the Merciful, the beneficial [in Arabic]
OM: Praise be to God, and prayers as well as peace be upon the prophet of God [in Arabic]. I let you know, I'm in Orlando and I did the shootings.
OD: What's your name?
OM: My name is I pledge of allegiance to [omitted].
OD: Ok, What's your name?
OM: I pledge allegiance to [omitted] may God protect him [in Arabic], on behalf of [omitted].
OD: Alright, where are you at?
OM: In Orlando.
OD: Where in Orlando?
[End of call.]
(Shortly thereafter, the shooter engaged in three conversations with OPD's Crisis Negotiation Team.)
2:48 a.m.: First crisis negotiation call occurred lasting approximately nine minutes.
3:03 a.m.: Second crisis negotiation call occurred lasting approximately 16 minutes.
3:24 a.m.: Third crisis negotiation call occurred lasting approximately three minutes.
In these calls, the shooter, who identified himself as an Islamic soldier, told the crisis negotiator that he was the person who pledged his allegiance to [omitted], and told the negotiator to tell America to stop bombing Syria and Iraq and that is why he was "out here right now." When the crisis negotiator asked the shooter what he had done, the shooter stated, "No, you already know what I did." The shooter continued, stating, "There is some vehicle outside that has some bombs, just to let you know. You people are gonna get it, and I'm gonna ignite it if they try to do anything stupid." Later in the call with the crisis negotiator, the shooter stated that he had a vest, and further described it as the kind they "used in France." The shooter later stated, "In the next few days, you're going to see more of this type of action going on." The shooter hung up and multiple attempts to get in touch with him were unsuccessful.
4:21 a.m.: OPD pulled an air conditioning unit out of a Pulse dressing room window for victims to evacuate.
(While the FBI will not be releasing transcripts of OPD communication with victims, significant information obtained from those victims allowed OPD to gain knowledge of the situation inside Pulse.)
4:29 a.m.: As victims were being rescued, they told OPD the shooter said he was going to put four vests with bombs on victims within 15 minutes.
(An immediate search of the shooter's vehicle on scene and inside Pulse ultimately revealed no vest or improvised explosive device.)
5:02 a.m.: OPD SWAT and OCSO Hazardous Device Team began to breach wall with explosive charge and armored vehicle to make entry.
5:14 a.m.: OPD radio communication stated that shots were fired.
5:15 a.m.: OPD radio communication stated that OPD engaged the suspect and the suspect was reported down.
Based on OPD radio communications, there were no reports of shots being fired inside Pulse between the initial exchange of gunfire between responding officers and shooter, and the time of the final breach. During this time, the shooter communicated with an OPD 911 operator and an OPD crisis negotiator, and OPD radio communications reported that victims were being rescued.
The FBI urges the public to provide information about the shooter and any contact they may have had with him. Since the release of the FBI's Seeking Information poster, the FBI has received thousands of tips. The FBI will investigate every tip.
In a press conference, U.S. attorney Lee Bentley said the redactions were made to avoid "re-victimizing" the survivors of the terror attack.