HAVERSTRAW, N.Y. (CBSNewYork) — A mystery was unraveling late Wednesday in Rockland County, after a local police officer shot and killed himself outside a school as the FBI stopped him in his car.

As CBS2’s Ali Bauman reported, it could all be connected to a quadruple murder a county over in Orange County.

The FBI said when agents pulled over a car on Rosman Road near Langschur Court in the town of Haverstraw at 8:20 a.m. Wednesday, the driver pulled out a firearm and killed himself with a shot to the head.

What followed was hours of heavy FBI and New York State Police presence, blocking off the residential street and leaving neighbors concerned.

“I really didn’t know what’s going on,” one neighbor said.

Sources told CBS2 the driver – Haverstraw police Officer Gerard Benderoth – was being investigated in connection with former Briarcliff Manor police Officer Nicholas Tartaglione. The latter was arrested in December in the murder of four Orange County men – Martin Santos-Luna, Miguel Sosa-Luna, Urbano Morales-Santiago, and Hector Gutierrez – who had all disappeared months before.

Tartaglione was also arrested on allegations that he was selling cocaine. It is believed that at least one of the victims was involved in drug trafficking.

On the quiet streets of Haverstraw, residents were shocked by the connection – remembering Benderoth as having a warm heart.

“Always had his kids with him, you know, just seemed like a regular, you know, nice guy – always plesant to us,” said deli worker Lisa Hanson. “You know, just a regular guy.”

In addition to his career as an officer, Benderoth was also a strongman competitor. The Rockland County native was a known figure in the community, and his weightlifting photos hung in his regular deli.

The FBI and state police said they were still investigating late Wednesday afternoon. CBS2’s Bauman tried going to Benderoth’s home, but his family declined comment.