Mourners hug as they pay their respects at a memorial in front the Dr. Phillips Center for the Performing Arts for the victims of the Pulse gay nightclub shooting where Omar Mateen allegedly killed 49 people on June 13, 2016 in Orlando, Florida. Joe Raedle/Getty Images

As more details emerge about Pulse nightclub killer Omar Mateen, investigators said Friday they’ve recovered security camera data from Sunday morning’s massacre.

While it’s not clear what’s the footage depicts, a law enforcement official told the Orlando Sentinel that it shows enough to help authorities piece together what happened early Sunday morning as part of their investigation.

Meanwhile, a profile of the 29-year-old killer who was gunned down by police during his murderous, homophobic rampage, is starting to come together. It not only depicts a former school bully and failing student who grew up to be an abusive spouse and an alleged stalker, but also a man who became eligible for a law enforcement academy in the state of Florida despite being fired from a job at the state’s Department of Corrections.

The New York-born son of Afghan immigrants had twice taken tests to become a Florida police officer, according to NBC News: once in 2011 and again in 2014. He failed the first test but passed the second one.

Omar Mateen
An undated photo from a social media account shows Omar Mateen, who Orlando police say was responsible for the mass shooting at a gay nightclub in Orlando, Florida, on June 12, 2016. Omar Mateen via Myspace/Handout

The tests indicate that Mateen strongly considered entering law enforcement about four years after he was fired from the Florida Department of Corrections about six months after taking the job in April 2007.

"Omar Mateen was not fit to serve as a member of the FDC [Florida Department of Corrections] team, as he was unable to meet the basic requirements of the correctional officer academy," the department said in a statement to NBC on Friday.

It was after his discharge from the FDC that Mateen became a security guard for British-based security firm G4S Secure Solutions in Jupiter, Florida, a job he held until he was killed Sunday. (As a G4S employee, Mateen was captured in the 2012 documentary “The Big Fix,” about the 2010 Deepwater Horizon oil spill in which he cynically complained that oil-spill cleanup workers were “hoping” for more oil so they could have jobs.)

Around the time of his short stint as a state corrections officer in 2007, Mateen reportedly became obsessed with a female bartender from Fort Pierce, Florida. His pursuit of her, which included inappropriate messages to Heather LaSalla’s Facebook profile, never elevated to the point where she reported the harassment to authorities, she said.

"He was one of those guys who wouldn't leave me alone," LaSalla told the Associated Press on Friday. "He was always like a loner.”

Mateen’s apparent personal difficulties began at about fifth grade when he was about 10 years old, not long after his parents moved from New York City to Florida in 1991 when he was about 5 years old, according to the Daily Beast. But as early as third grade he was talking frequently about sex and violence, and was suspended for a total of 48 days in high school.

With an unremorseful, violent temper and a poor academic record, Mateen became increasingly virulent. Mateen’s former elementary school teacher, Kathleen Zurich, told the New York Daily News that Mateen’s father Seddique was lenient on numerous occasions when teachers reported his abusive behavior.

The profile coming together about Mateen has one stark missing element: Any proof at all beyond his own words that he had any real connection to Islamic terrorists. Instead, the profile depicts a man who showed signs of trouble dating back to childhood.