Orlando Shooting Latest: Partial Transcripts of Calls Between Gunman and Police to be Released

Authorities will release partial transcripts of the calls between Orlando gunman Omar Mateen and hostage negotiators as the investigation into what motivated Mateen to open fire and kill 49 people and injure dozens more at a gay nightclub moves forward.

Speaking on ABC's "This Week," U.S. Attorney General Loretta Lynch said authorities are going back to learn everything they can about the killer and build a profile as they move forward to prevent a similar attack in the future. Lynch said as authorities retrace the days, weeks and months of the killer's life, they are asking the public to come forward with any information they might have about the gunman, such as the gun shop owner who told authorities Mateen had been in the shop and was acting suspiciously.

Lynch said because Mateen did not make a purchase there was no record or identifying information about the killer at the time.

On CBS's "Face the Nation," Lynch said investigators are concerned about the motivations that led Mateen "to that particular club at that particular place," as authorities are aware he had some issues with the LGBT community.

The partial transcripts that will be released Monday will not be broadcasting Mateen's pledges of allegiance to ISIL so as not to re-victimize those who went through the attack. In his calls with 911 and hostage negotiators, Lynch said Mateen made no mention of the LGBT community.

She came out in favor of current legislation that would prevent those on terrorist watch lists from buying guns. The Senate will vote on two versions of the legislation on Monday, both of which previously failed in December. Mateen had been placed on a terror watch list when he was questioned by the FBI in 2013 and 2014 but was subsequently removed from the list when the FBI found no conclusive evidence linking him to terrorism.

New details have emerged daily detailing the gunman's troubled past, going back as early as when Mateen was in elementary school. Recent developments include information that he was in constant trouble in school and in 2007 asked a fellow classmate at a law enforcement academy whether the classmate would report him if he brought a gun to school.

The attorney general will be traveling to Orlando on Tuesday to meet with the victims, first responders and other members of the community impacted by attack.

Photo courtesy of the City of Orlando Facebook page