Orlando killer threatened explosive booby traps

ORLANDO, Fla. - As investigators continued Wednesday looking deeper into whether the wife of mass killer Omar Mateen had prior knowledge of his plans, more details emerged about his attack early Sunday on a popular gay nightclub - including worries Mateen strapped explosives to some of his hostages.

Noor Z. Salman - who married Mateen, 29, in 2011 - went with him at some point to buy ammunition, according to a U.S. law enforcement official familiar with the probe. The FBI also learned from interviews with Salman, 30, that she accompanied him on at least one trip to the Pulse gay nightclub before the attack.

The official said Salman warned Mateen not to carry out an attack, apparently as he was leaving their Port St. Lucie, Fla., home Saturday night for Orlando.

The official, whom the Washington Post did not name. said the couple surveilled the club between June 5 and 9. FBI officials said Mateen bought guns used in the attack in early June.

Investigators were still working to corroborate Salman's story.

'With respect to the wife, I can tell you that is only one of many interviews that we have done and will continue to do in this investigation,” FBI Special Agent Ron Hopper told a news conference.

CNN reported that a U.S. attorney plans to present evidence to a federal grand jury to determine if charges will be brought against Salman.

As investigators looked into her, authorities disclosed new details about the attack at Pulse, which left 49 people dead and dozens wounded in what was the deadliest mass shooting in U.S. history.

Mateen made multiple calls from inside the club during his rampage, which he used to declare his allegiance to various Islamist militant groups.

He called local cable news channel News 13, the station revealed Wednesday.

Matthew Gentili, who was the producer on duty at the time, described the call in an interview with the station.

''I'm the shooter. It's me. I am the shooter,'” Gentili described Mateen as saying. Gentili said Mateen also told him, ''I did it for ISIS. I did it for the Islamic State.'”

In a 911 call, Mateen said he was strapping explosives onto four hostages and stationing them in the building's corners, Orlando Mayor Buddy Dyer said.

That claim was bolstered by the accounts of survivors, many of whom were on the phone to 911 or texting and calling family members, passing along word of the same threat, Dyer said.

'They independently were saying, ‘Yes, the bomber is starting to put on explosive vests,'” Dyer said.

That threat prompted police to mount their raid at 5 a.m. Sunday. They punched a hole in a wall and fatally shot Mateen in a gunbattle.

Near his body, they found a battery pack they believed might be a detonator and a bag they had initially feared contained explosives.

Officials would not say if they actually found any explosive booby traps.

Among the many unanswered questions is whether Sunday's slaughter at the gay club was an act of politically driven rage or triggered by personal demons - or a mix of both. Without an apparent manifesto or video message by the shooter, investigators have looked for clues among survivors and former friends to dig into his psyche.

Wider probes stretched this week from a quiet town north of San Francisco to a German bank as the gunman's family came under increasing scrutiny.

Three people identifying themselves as FBI agents conducted interviews Tuesday in the neighborhood in northern California where Mateen's wife, Noor Zahi Salman, was raised in a family with Palestinian roots, the Associated Press reported.

German investigators examined a Düsseldorf bank account held by Mateen's father, Seddique Mateen, who has said his son visited him at his Port St. Lucie, Fla. home a day before the attack.

Agents appear to be determining his income sources and how he spent money he had solicited online in 2013.

The Washington Post, the Orlando Sentinel, Reuters and Newsday contributed to this report.