One of the three suspects being sought in connection with a brazen heist at a Manhattan Cartier store earlier this year accidentally shot himself when he thought he was about to be arrested at a Brooklyn home on Halloween, according to a law enforcement source familiar with the case.

The FBI had been looking for Ralik Hansen and two other men they say were members of the crew that robbed a Cartier store on Fifth Avenue in January, stealing $700,000 in merchandise from the high-end jeweler.

The source says Hansen accidentally shot himself inside an apartment on Snediker Avenue in Brownsville Oct. 31. He apparently got the weapon with the intention to fight off investigators he believed were there to arrest him when it went off; there were no investigators who had come to the home.

Agents continue to look for Courtney Hardin and Jamal Dehoyos in connection with the heist, which netted at least 16 watches.

Several suspects were charged in the robbery earlier this year. They were accused of being part of a violent interstate robbery crew that hit the Borgota Hotel and Casino in Atlantic City, a jewelry store in Richmond, Virginia, and another store in Cranford, New Jersey.

A stun gun was used on a store worker in at least one of the hold-ups.

Hardin, 25, also goes by "Mazie" and "Mozie" and is known to frequent Bedford-Stuyvesant and Crown Heights in Brooklyn. Dehoyos is 38 or 39 and is known to frequent East New York in Brooklyn and Flushing and Springfield Gardens in Queens, officials have said.

Authorities have offered a significant reward for tips leading to their arrests. Anyone with information about the suspects is asked to call 212-384-1000.