The woman struck and killed in Warwick by a high-speed Amtrak train Tuesday night has been identified as a former Amtrak conductor from Marshfield, Mass., according to the Warwick police, who said yesterday they think the death was a suicide.

Anne L. Coyne, 38, had argued with her boyfriend that morning and said she was going to kill herself, according to Maj. Joseph H. Tavares. After she left him, the boyfriend filed a missing-person report with the Marshfield police, Tavares said.

Coyne was struck shortly before 10 p.m. on a remote stretch of rails, near Lincoln Park Cemetery, where Amtrak’s Acela is authorized to reach a speed of 150 mph. A conductor said he saw a woman running across the track in the instant before she was hit. It took the Boston-bound train a mile to come to a stop.

Coyne’s late mother’s Toyota Camry Solara had been left with the keys in the ignition in the lot of Lincoln Avenue Auto and Truck, a service garage along the tracks. The garage owner called the Warwick police Wednesday after hearing media reports about the woman killed on the tracks, Tavares said. The police found Coyne’s purse and her license inside the unlocked car, Tavares said.

The Warwick police checked her license and found the missing persons report, Tavares said. The fingerprints, tattoo on her right ankle of a smiling yellow sun, and physical description of the woman found at the tracks matched the woman missing from Marshfield. She was clothed in the gray hooded “South Boston” sweatshirt and dark blue jeans she was last seen wearing when she left Marshfield that morning. The police notified Coyne’s family late Wednesday night.

The police said that Coyne had worked as a conductor for Amtrak; her name was listed on a 2004 roster for the Massachusetts Bay Commuter Railroad.

Tavares said the police did not know what drew her to this remote spot.

“It’s unfortunate when something like this happens,” Tavares said. “She was just 38. We may never know why.”

amilkovi@projo.com