Federal investigators promised to provide more insight as to what was happening inside the Pulse nightclub after a gunman started a deadly assault that was the worst mass shooting in modern U.S. history.

The FBI was releasing on Monday a printed, partial transcript of the conversations between the gunman within the Pulse nightclub and Orlando police negotiators, U.S. Attorney General Loretta Lynch said.

The release is coming a day after tens of thousands of people held a candlelight vigil in the heart of downtown Orlando for the 49 victims who died in the massacre. The victims also were remembered at church services and at makeshift memorials throughout Orlando.

Lynch said in interviews Sunday on several news shows that the FBI would release a partial, printed transcript of the conversations between gunman Omar Mateen from within the Pulse nightclub and Orlando police negotiators. Armed with a semi-automatic weapon, Mateen went on a bloody rampage at the club June 12 that left 49 people dead and 53 others seriously hurt. Mateen died in a hail of gunfire after police stormed the venue.

Lynch told ABC’s “This Week” that the top goal while intensifying pressure on the Islamic State — the extremist group thought to have inspired Mateen — is to build a complete profile of him in order to help prevent another massacre like Orlando.

“As you can see from this investigation, we are going back and learning everything we can about this killer, about his contacts, people who may have known him or seen him. And we’re trying to build that profile so that we can move forward,” Lynch said.

Lynch said she would be traveling to Orlando on Tuesday to meet with investigators.

(AP)