A state trooper was on his phone chatting with a woman he had met on the sex-and-dating app Tinder when he struck and killed a 14-year-old girl, investigators said.

Theresa “Terry” DiFalco was a freshman at Westfield High School, taking part in a scavenger hunt with other theatre department students, when she was struck and killed on March 4, 2017.

Alexander Gelfand was driving an unmarked police vehicle, a Chevrolet Caprice, when he struck DiFalco around 8:30 p.m. that night on Central Avenue near the intersection with Wyoming Street. His shift had ended by 5 p.m. that day.

Prosectors determined in May 2017 that the trooper would not face criminal charges in what the office called a “tragic accident."

Gelfand, however, is being sued by DiFalco's family.

Court documents filed Oct. 14 by DiFalco's attorney include both out-of-court testimony from Gelfand and a supplemental 2017 report from the Union County Prosecutor's Office, which say that Gelfand sent and received a pair of text messages with a woman he had met hours earlier at her home after they had connected on Tinder.

NJ.com first reported this week about this detail in the litigation.

According to testimony he gave in a deposition in October 2018, Gelfand said he left the woman's house in Matawan after spending about two hours there and said he was driving to his home in Scotch Plains at the time of the crash.

Gelfand's cell phone sent an outgoing text at 8:29 p.m., which said "I had fun, you're sweet and I want to see you again," according to the Prosecutor's Office report dated March 16, 2017.

The same report said an incoming text also at 8:29 p.m. from the woman said, "Ok we can do that."

During the same deposition, Gelfand said he didn't recall when he wrote the text, and didn't recall if he stopped for any lights after exiting the Garden State Parkway the night of the accident.

Gelfand also said he didn't remember if his phone was in the car's cup holder or if it was against his leg at the time, "but I know that prior to the accident and during the accident the phone was not being looked at and I was not holding on to it."

"Honestly, if I wasn't looking straight ahead, I would feel very different about the situation and I'd have a much more difficult time because I'd feel like it was my fault for not paying attention, but that's not the case. I was looking straight ahead," Gelfand said in the deposition.

There also is conflicting information about whether any school officials, including the educator who leads the theatre department, were aware of the scavenger hunt.

Maureen DiFalco, Terry's mother, said in the lawsuit that it was a well-known annual tradition at Westfield High School for students involved in the spring theatre production.

Included in the lawsuit are screenshots of text messages that appeared to be between DiFalco and another student, showing that DiFalco voiced reluctance about taking part in the hunt at all, saying she was tired.

In another text, DiFalco asked if everyone would "hate" her if she didn't show up for the event.

There also are records of DiFalco's last text exchange with her mother, as she set out with four other students as a team for the scavenger hunt.

DiFalco suffered a broken neck, broken pelvis, broken leg and other injuries in the deadly crash, according to the medical examiner's report.

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