A veteran NYPD homicide detective who went missing on Thursday, sparking a massive manhunt, was found dead of an apparent suicide, police sources said.

Read Veteran NYPD Chief Dies by Suicide Before Mandatory Retirement

The body of Joe Calabrese, 58, was found near bushes in Plumb Beach in Brooklyn Thursday afternoon, dead of an apparent self-inflicted gunshot wound to the head, the New York Post reports.

"I don't understand it. I don't understand why he would do this," said a stunned police officer who knew Calabrese.

Calabrese didn't report to work Thursday and was unreachable, a high-ranking police source said.

Earlier Thursday, at least 100 uniformed and plainclothes officers swarmed the parking lot of the Plumb Beach rest area where Calabrese's Cadillac was parked.

Calabrese's death comes just a day after Steven Silks , the NYPD deputy chief of Queens North, fatally shot himself in the head Wednesday while sitting in an unmarked patrol car. The 62-year-old chief had been weeks away from his scheduled mandatory retirement.

Editor's Note: If you or someone you know has ideation of suicide or is approaching crisis, please know that the National Suicide Prevention Lifeline (1-800-273-8255), provides 24/7, free and confidential support for people in distress. Safe Call Now (1-206-459-3020) offers those services specifically for first responders.

On a website maintained by BlueH.E.L.P.—an organization that tracks officer suicides while simultaneously seeking to prevent such tragedies from occurring—a first responder need only enter a few data points—such as their location and what kind of assistance is needed—and the individual will be provided with a list of options for help from a searchable database dedicated to helping first responders find emotional, financial, spiritual, and other forms of assistance.