Terror suspect Omar Mateen made one last attempt to become a full-fledged police officer last summer when he applied for an intensive six-month law enforcement academy in his hometown of Fort Pierce, Daily Mail Online has learned exclusively.

But officials at the Indian River State College's Criminal Justice Institute were so concerned about his behavior that they rejected his application and reported him to the Florida Department of Law Enforcement, a source familiar with Mateen's application said.

'In the light of what happened in Orlando this weekend, I believe he was trying to infiltrate the school to understand how policing works on a day-to-day basis,' the source said.

'I believe he wanted to find a way to get hired by a police force after the end of the program and carry out whatever nefarious plan he may have had while in a uniform.'

It wasn't the first time that Mateen applied for a law-related job.

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Omar Mateen, wearing an NYPD T-shirt, was kicked out of the police academy at Indian River State College last summer. 'I believe he wanted to get hired by a police force to carry out whatever nefarious plan he had while in a uniform,' said an informed insider

Students at the Indian River State College Criminal Justice Institute in Fort Pierce

Staff at the Institute were so concerned about Mateen's behavior they rejected his application and reported him to the Florida Department of Law Enforcement, a source familiar with Mateen's application

In the late 2000s the source said, Mateen was hired by the Florida Department of Corrections to be a prison guard.

The department, however, told Mateen he'd need additional training at the Criminal Justice Institute before he could start.

So Mateen passed the rigorous application process and was accepted. After about a month of instruction, however, Mateen quit without as much as an explanation.

'He just stopped showing up,' the source said. 'But he passed the state's screening process as well as the school's. All he had to do to work in a prison was to get a decent grade in his classes and graduate.'

Mateen, 29, graduated from the two-year Indian River State College's law enforcement program after high school in 2006, according to school spokesman Robert Lane.

The program, however, was purely academic and centered on the philosophy, history, administration and broad-brush principles of policing.

The school's Criminal Justice Institute, however, is where candidates get hands-on training from retired prison guards and police officers.

WEIGHTS, PROTEIN POWDER AND GROWTH HORMONE - HOW HE BULKED UP Omar Mateen desperately wanted to be a law enforcement officer, according to a former classmate, but it may have been for the wrong reasons. Mateen, one source tells the Daily Mail Online, was bullied in high school. 'Some kids picked on him,' said a former classmate of Mateen at Martin County High School, which he attended in the early 2000s. 'It had nothing to do with him being an Arab [sic]. It had to do with the fact he was 150 pounds wet and rather short. 'There's no doubt he was obsessed with being a cop because he wanted to assert some authority. He loved being with the big boys. He just wanted to belong, but he wasn't that kind of a guy who could belong.' At first, the ex-friend said, Mateen started lifting weights in the school's football team area. 'The school had a state-of-the-art weight room,' the source said. 'I was a big boy so I spent hours in there. Omar started coming in regular. We sorta make fun of it but he became a spotting partner to all the muscle guys.' In time, the friend said, Mateen was physically unable to grow as big as his training friends. So, he started using growth hormones. 'He used to come into the (GNC) nutrition store where I worked to get protein powders. One time, it looked like he had grown by 50 pounds in just a couple months. 'So he started bragging about shooting up steroids. He was way deep into it. You could tell. He had that rounded muscle look that just wasn't natural.' In time, Mateen also started working at the GNC store at the Treasure Coast Mall near Port St. Lucie. Upon graduation in 2003 Mateen, who had turned 18, enrolled in a vocational school at first. In 2004, he started in the criminal justice program at Indian River State College in his hometown of Fort Pierce. The college prides itself for its tuition 40 percent lower than most colleges, and for a recognized law enforcement academy. The two-year law enforcement program had become a forced passage for young adults in the area who want to become police officers or sheriff's deputies. It offers classes in the history, philosophy, organization, management and laws of policing. Training includes real-life action simulators and firearms certification. However, the friend said Mateen couldn't keep up with some of the classes. 'Two of us bodybuilders went into the same program as Omar,' he said. 'It was obvious he was having problems studying. It ended he couldn't pass a few tests and had remedial classes.' A spokesman with Fort Pierce Police said Mateen never applied for an officer's job with the agency. 'We don't have any records of him putting in for a job here,' said Public Information Officer Ed Cunningham. And Bryan Beaty, a spokesman for the St. Lucie County Sheriff's Office, said Mateen never applied with that agency either. There may have been a good reason for that. 'At one point, he admitted he couldn't pass a psychological exam and you could tell the air had just run out of him,' the former classmate said. 'That's why he ended up a security guard.' Advertisement

When Mateen returned to the Institute with paperwork indicating he wanted to be certified as a police officer in June 2015, according to the source, his application for police training was rejected quickly.

'The application process is a 25-page questionnaire plus a one-on-one interview,' the source familiar with the process tells Daily Mail Online. 'It's is very competitive since only 50 applicants are accepted into each six-month session.'

Mateen, the source said, showed up for his interview with an admissions coordinator with no answer to a series of questions.

One of them was whether he'd ever been the subject of an investigation.

It turns out that when Mateen arrived at the interview, he'd been questioned about terrorist activity twice in two years, according to FBI Director James Comey.

The FBI, however, cleared Mateen and he was free.

Mateen appealed his rejection rejection and returned to the school for another interview . 'He was with his dad,' the source said. Mateen's father, Afghanistan-born SeddiqueMir Mateen, stars on YouTube videos in camouflage outfits

'At the interview, he was aggressive from the moment he came to the office,' the source continues. 'Everything was an argument. Within three minutes, he started talking about how futile it was for him to apply. "You won't let me in because I'm a Muslim," he said.

'Religion isn't even a question on the application form. He volunteered that information. He wasn't asked. But that's all he kept talking about.'

Within days, the Institute notified Mateen it rejected the application.

'There were just too many red flags,' the source said. 'One of them was the fact this young man did not have the true motivation to be a police officer.

'The coordinator had no idea why Omar even wanted to be a cop because he couldn't even answer that simple question.

'All he wanted to talk about was that he was a Muslim and the school didn't want Muslims.'

On his application, the coordinator called Mateen 'deceptive and untruthful.'

Mateen then appealed the rejection and returned to the school for another interview with an IRSC vice president.

'He was with his dad,' the source said. Mateen's father, Afghanistan-born Seddique Mir Mateen, stars on YouTube videos in camouflage outfits where he says he is that country's president.

'Things got pretty heated in that office. For the two of them, it was clear that the school was racist and didn't want Muslim students, which is totally false. But the VP let them rant and, eventually, politely asked them to leave.'

Institute Director Dr. Lee Spector didn't return calls for comments about Mateen's interview, but on its website, the school cites its policy of non-discrimination on the basis of gender, age, race and religion.

After Mateen lost his appeal, a school higher-up called the Florida state police, the FDLE, to report Mateen as someone who should be watched.

The FDLE's response, according to the source was that Mateen was already on a watch list for potential terrorist affiliation.

In the end, the source said Institute officials now believe Mateen hoped to carry his bloody deeds in a police uniform.