Orlando gunman thought he would survive — and commit other attacks: police
Omar Mateen is seen in a documentary about BP, "The Big Fix." (YouTube)

Omar Mateen -- who killed 49 people and wounded 53 others in the massacre at an LGBT Orlando club earlier this month, might have been planning to carry out other shooting attacks, WFTV-TV reported.

Investigators have developed a theory that Mateen expected to escape the Pulse nightclub and strike other targets, including the local House of Blues restaurant, after discovering "a lot of ammunition" in the truck he parked near the club, instead of the bombs he falsely claimed were inside.

WFTV cited three unnamed sources who said that after opening fire inside Pulse at 2:02 a.m. local time on June 12, Mateen was making his way outside when he was confronted by an off-duty police officer and exchanged gunfire, forcing him back into the venue. Mateen subsequently hid inside a bathroom.

The Orlando Sentinel reported that Mateen exchanged gunfire with Officer Adam Gruler around that time, and then engaged in a further firefight with six officers before retreating.

Mateen was killed during a firefight with 13 officers around 5:14 a.m., when he emerged from one of several holes detonated by the bomb squad.

Watch WFTV's report, as aired on Thursday, below.