The US attorney general on Sunday announced plans to release transcripts of phone calls between negotiators and the gunman who killed 49 people in a gay nightclub last week.
Loretta Lynch made the announcement as Orlando, Florida, before a public memorial service that drew thousands of people on Sunday evening.
The transcripts, which will be released in limited written form, will show what gunman Omar Mateen told law enforcement as the events unfolded, Lynch said on CNN.
"The reason why we're going to limit these transcripts is to avoid re-victimizing those people that went through this horror. But it will contain the substance of his conversations," she told the network.
The recordings are part of a massive investigation into what motivated Mateen to carry out the worst mass shooting in modern US history.
Mateen used a semi-automatic weapon and a handgun in the bloody rampage at the nightclub in the early hours of June 12. In addition to killing 49 people, he wounded another 53, and four of them remain in critical condition. Mateen died in a shoot-out after police stormed the venue.
Lynch said during the three calls made from the nightclub, Mateen talked about his pledges of allegiance to a terrorist group and his motivations for committing the killings. Investigators already had said that in one of the calls he pledged allegiance to Islamic State.
"He talked about American policy in some ways," Lynch said.
The Department of Justice on Sunday also announced that Lynch would travel on Tuesday to Orlando to meet with victims, first responders and other members of the community whose lives have been affected by the attack and receive information about the investigation.
US investigators "are going back and learning everything we can about this killer, about his contacts, people who may have known him or seen him," she said on US television network ABC.
The memorial service Sunday evening was held at Lake Eola Park in the heart of Orlando. Peolple lit candles, held rainbow flags and carried flowers and giant banners.
The service began with a mass. The Orlando Gay Chorus performed and the names of the 49 victims were read, each accompanied by a chime.
"Hate is easy, love takes courage," the clergyman said. Several of the victims already have been buried, according to US news reports.
In the central Florida city that is the home of Disney World and other amusement parks, people left balloons, flowers, pictures and posters at the site to honour the victims.