New York City police are still trying to figure out what motivated a former federal employee to fatally shoot a security officer inside of a federal office building in Manhattan on Friday before taking his own life.

Officials say that 68-year-old Kevin Downing of Fort Lee, New Jersey entered the building using the West Houston Street entrance in lower Manhattan and opened fire at 5:05 p.m., reports CBS New York. That's where he shot a 53-year-old security officer named Idrissa Camara in the head in the security screening area. Downing then turned his weapon on himself and was pronounced dead on the scene. Meanwhile, Camara died shortly before 6 p.m. in a hospital, police said.

New Jersey Rep. Bill Pascrell identified the shooter as a whistleblower who had been given "a raw deal" by the Bureau of Labor Statistics, which fired him in 1999. However, Pascrell added that he has no idea what triggered the military veteran to commit such a heinous act.

"What made him snap?" Pascrell told The Associated Press. "I don't know."

Federal documents show that after Downing was terminated from a job at the New York City office of the Bureau of Labor Statistics, he appealed the firing on the grounds that he had been targeted because he was a whistleblower. Later on, his live-in fiancée died of breast cancer. His house was also in foreclosure, and he suffered health problems due to a car accident, Pascrell said.

"None of this at all ever indicated to any of us that this was going to happen," Pascrell said.

"We're in the very early stages of the investigation and are working to establish his motive for coming here, if he had an intended target beyond the security officer, and what the motive was behind the crime," said James O'Neill, a chief with the New York Police Department.

Although the Bureau of Labor Statistics has an office in the building where the shooting took place, it was not clear whether Downing had once worked there.