Quay-Sean Hines.

An ex-boyfriend who killed a New York state woman soon went to a local gym after the act, according to authorities.

Quay-Sean Hines, 30, is charged with murder in the second degree after allegedly shooting and strangling Amelia Laguerre, 33, according to local outlets.

Police said the former couple dated for almost two years until breaking up in late 2021. Hines allegedly carried a torch in disturbing fashion.

Violent and emotionally abusive, he began stalking Laguerre, showing up unannounced at her job in attempts to continue their relationship, police Capt. Stephen Fitzpatrick said, according to NBC New York.

Hines allegedly did things like burn clothes and break into Laguerre’s apartment.

That culminated in horrifying fashion. Hines allegedly ambushed Laguerre on March 31 in an underground parking garage near Northwell Health, where the slain woman was a staff member.

“He immediately came up behind her, shot at her ten times, strangled her nine times,” Fitzpatrick said in an WABC report.

Hines soon went to an LA Fitness, authorities said.

“According to the preliminary investigation, less than one hour after Hines allegedly shot Ms. Laguerre, he went to the gym,” District Attorney Anne Donnelly said. She ripped into Hines, calling the alleged murder “a selfish act, a calculated act and a cowardly act.”

Hines pleaded not guilty at his arraignment.

[Booking photo via Nassau County Police Department]