The high school senior made eye contact with Brian Kennedy as the 34-year-old Devon man walked into his neighborhood Wawa on a March night armed with an AR-15.

Behind the register, Patrick Winnemore, 18, watched in horror as Kennedy walked around the store, holding the long, black weapon that “looked like something they might use in the Army,” he said.

Within seconds, the teen said, Kennedy stopped, fired repeatedly, and fled, leaving his ex-wife, Stephanie Miller, dead on the floor between the coffee island and the deli counter.

The young cashier calmly recalled those harrowing details Thursday as he testified at Kennedy’s preliminary hearing on murder charges. After the brief proceeding, District Judge Leon Hunter III ordered that Kennedy stand trial on charges of first- and third-degree-murder, reckless endangerment, and related crimes.

In a red prison jumpsuit, a pale, dark-haired Kennedy sat quietly beside his attorney. Two of Miller’s friends attended the hearing in a heavily guarded Newtown Square courtroom as more than a dozen uniformed officers looked on. The judge acknowledged that the case is an especially emotional one, but warned that outbursts or comments from the gallery would not be tolerated.

About 8:20 p.m. on March 28, authorities say, Kennedy walked into the Sugartown Road Wawa in Radnor Township with a DTI AR-15 semiautomatic rifle that he had legally purchased 12 days earlier. Winnemore said he recognized the man, a regular customer.

Miller was at the store expecting to pick up their 6-year-old son, but Kennedy arrived alone, gun in hand.

For years, court records show, Kennedy and Miller had exchanged custody of their son at the Wawa. During one of those exchanges at the store in 2016, Kennedy threatened to kill Miller, a 37-year-old occupational therapist, whispering in her ear, “Get that [expletive] life insurance policy before I kill you,” according to a protection-from-abuse order Miller filed after the incident. That order lapsed this fall.

The couple’s 2013 divorce angered Kennedy, court records show, and he wanted more time with their son after they split. Hundreds of pages of court documents in Delaware and Chester Counties show how hard Kennedy tried to expand their child-custody arrangement, which limited his time with his son to three days during the week.

At Thursday’s hearing, Delaware County Assistant District Attorney Michael Mattson called only one witness, Winnemore, the Conestoga High School senior who said he watched the terror unfold in the middle of his evening shift as a Wawa cashier.

“I saw him immediately,” he said of Kennedy. “He looked very angry and determined.”

At the time, he said, three other employees and about eight customers were inside the small, older-style Wawa off Lancaster Avenue.

Kennedy stood next to the coffee island, about three feet from Miller, as he quickly and methodically fired at her five or six times, said Winnemore, who ducked behind the register after the shooting began. Kennedy then made a loop around the registers, the teen said, and walked out. The murder took all of 30 seconds.

When he peered out from behind the counter, Winnemore said, he saw Miller on the ground in the store’s back corner, surrounded by spent shell casings.

“She was on the ground," he said, “not moving, with bullet holes.”

He scrambled for the store phone and dialed 911.

Police found Kennedy later that night, overdosed in his car in a Glen Mills park 15 miles from the Wawa. Police took him to the hospital, where he recovered, and was later taken to the Delaware County Correctional Facility. He is being held without bail and is set to be formally arraigned later this month.

Kennedy said nothing to reporters as he arrived for court Thursday. His lawyer, Michael Dugan, declined to comment.