A cold-hearted thief fatally shot a Louisiana gas station clerk at close range — even after he calmly handed over all the money in the register, police said.

Two men entered a Shell gas station in Kenner at 2 a.m. Monday and walked around as if they were about to buy something before one approached the clerk, police said.

One suspect in a white knit cap and black face mask then pulled out a handgun and demanded money while the second man stood by the door.

Investigators said the gunman opened fire “without provocation” after the clerk, identified by his wife as Abd El Ghader Sylla, handed over all the money from the register.

Sylla was shot once in the chest while on his knees with his hands up, apparently begging for his life, police said. He was later pronounced dead at a hospital.

“This was a brutal and senseless murder,” police wrote in a statement accompanied by surveillance photos of the suspects.

No arrests had been made as of midday Tuesday, but investigators believe they’re close to identifying a vehicle used by the suspects to flee the gas station, Kenner police Lt. Michael Cunningham told The Post.

The clerk’s widow, meanwhile, said she and Sylla had a 1-year-old daughter together and were expecting their second child in February.

“They had what they had come for, what they needed,” DeVona Tibbet told NOLA.com. “I don’t understand why they needed to hurt him.”

Video footage from inside the gas station shows Sylla emptying the register and handing over the cash to the gunman before he was murdered, Cunningham told the outlet.

Sylla, who came to the US about a decade ago from Mauritania in northwest Africa, did exactly what authorities recommend to survive being robbed, Kenner’s top cop said.

“There was no resistance on [Sylla’s] part at all,” Police Chief Michael Glaser told the outlet.

“He did whatever they told him to do. There’s no way to explain why the clerk was shot. It just makes no sense.”