NEW YORK - A man who gunned down a security guard at a federal building in Manhattan before killing himself was a whistle-blower who had been given "a raw deal" by the agency that fired him, a New Jersey congressman who took up the man's case said Saturday.

Rep. Bill Pascrell (D., N.J.) said he did not know what made Kevin Downing, a military veteran who had once been employed by the Bureau of Labor Statistics, open fire at the New York federal building on Friday.

"What made him snap?" Pascrell said to the Associated Press in a telephone interview. "I don't know."

Downing had endured a string of misfortunes as his live-in fiancee died of breast cancer, his house was in foreclosure, and he suffered health problems himself, Pascrell said.

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

Federal agents swarmed Downing's home in Fort Lee, N.J., hours after shooting, searching for anything that could help them understand his motive.

Downing, 68, opened fire Friday at the federal building that houses an immigration court, passport processing center, and a regional office for the Department of Labor.

As he approached a metal detector, Downing shot FJC Security Services guard Idrissa Camara, police said.

After shooting the senior security guard in the head at close range, Downing walked toward an elevator where he encountered another employee, and then shot himself in the head, said James O'Neill, a chief with the New York Police Department.

There was no indication the shooting was terrorism-related, O'Neill said.

Dowling had been fired from a job at the New York City office of the Bureau of Labor Statistics in 1999 and appealed the firing, claiming he had been targeted because he was a whistle-blower.

Pascrell said Downing contacted his office after the Democrat became Downing's congressman in a 2013 redistricting.