Interesting developments.  If you look at Mateen’s apartment pictures shared via Daily Mail, it would appear nothing was amiss.  No obvious signs of packing up, no removal of personal items, nothing which would suggest a long-term pre-planned exit for either Omar Mateen or his wife Noor Zahi Salman and their 3-year-old son.
The apartment appears as if someone was just gone to work, etc. – SEE HERE –
Now witness reports are surfacing that Omar Mateen was a regular visitor to the Pulse nightclub [Orlando Sentinel], and the LA Times has a witness report from a patron who exchanged messages with him via a Gay Dating App.
(LA Times)  […]  Kevin West, a regular at Pulse nightclub, said Omar Mateen messaged him on and off for a year before the shooting using the gay chat and dating app Jack’d.
But they never met – until early Sunday morning.
West was dropping off a friend at the club when he noticed Mateen – whom he knew by sight but not by name – crossing the street wearing a dark cap and carrying a black cellphone about 1 a.m., an hour before the shooting.
“He walked directly past me. I said, ‘Hey,’ and he turned and said, ‘Hey,’” and nodded his head, West said. “I could tell by the eyes.”
At least four regular customers of Pulse, the lesbian, gay, bisexual and transgender nightclub where the massacre took place, told the Orlando Sentinel on Monday that they believed they had seen Mateen there before.
“Sometimes he would go over in the corner and sit and drink by himself, and other times he would get so drunk he was loud and belligerent,” said Ty Smith, who also uses the name Aries.
He saw Mateen at the club at least a dozen times, he said.
“We didn’t really talk to him a lot, but I remember him saying things about his dad at times,” Smith said. “He told us he had a wife and child.”
As soon as West saw photos released of Mateen after the shooting, he said, he drove to his local police station, where officers summoned FBI officials, who showed him a photo of Mateen on a computer screen.
“I said, ‘That’s him,’” West said, and turned over his phone and Jack’d log-in information to the FBI, which still had the phone late Monday, he said.  (read more)