A New Jersey State Trooper died Sunday after being struck by a vehicle along Route 195 in Howell Township in Monmouth County.

Trooper Marc K. Castellano, 29, was investigating an abandoned car along the Exit 31 westbound ramp in around 10 a.m. Sunday morning when he was hit by another vehicle, Capt. Gerald Lewis said.

Attempts were made to revive Castellano at the scene, witnesses said.

Police did not say if the incident was a hit-and-run, or if they knew the identity of the driver that struck Castellano.

"The investigation into this incident is ongoing," Lewis said.

The driver of the abandoned vehicle which Castellano had stopped to investigate, Diana Hoffman, 30, of Blackwood, was found by police hiding in a wooded area near the road. Charges against her are pending, Lewis said.

Hoffman told police that an unidentified male had been with her in the car. Dozens of local and state police, including K-9 and helicopter units, combed the accident scene with traffic backed up for miles along 195. A command post was set up at a nearby auto dealer lot.

By late afternoon, a search of the area for that suspect had been suspended after police began questioning "the validity" of Hoffman's claims, Lewis said.

The Associated Press reported that four law enforcement officials were taken to a local hospital for treatment related to heat exhaustion during the search.

Castellano, of Howell, was a 5-year-veteran, and a member of the Troop "C" Tactical Patrol Unit. He was married with with a 4-year-old daughter and a 1-year-old son.

Gov. Chris Christie called for prayers for Castellano at an early Sunday afternoon event before visiting Castellano's family at Jersey Shore Medical Center.

Castellano's family members could not be reached for comment.

"The loss of Trooper Castellano is a difficult blow to absorb," said State Police Superintendent Colonel Joseph R. Fuentes. "[He] was the embodiment of the finest ideals of the New Jersey State Police."

Contact staff writer Mike Newall at 856-779-3237 or mnewall@phillynews.com.