A clip has surfaced from a documentary focused on the 2010 Deepwater Horizon oil spill in the Gulf of Mexico, which showed Orlando nightclub gunman Omar Mateen talking about the environmental disaster while working as a security guard.

Mateen was filmed secretly by the makers of the 2011 documentary, "The Big Fix," as he guarded a beach at night in Pensacola, Florida where the clean up was taking place.

In the video, he disparages workers who were cleaning up the spill saying they wanted the disaster to continue so they would have jobs.

The filmmakers, Josh and Rebecca Tickell, said in a statement on Wednesday that they had turned the footage over to authorities.

Mateen opened fire on Sunday in a gay nightclub in Orlando, killing 49 people and injuring dozens more in the worst mass shooting in modern U.S. history.

He was shot dead by police after a three-hour rampage through the nightclub.

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