Cops have arrested a crazed man suspected of shooting and killing a Nassau County cop — then killed another motorist as he made his getaway, law-enforcement sources told the Post.

Artie Lopez, an Emergency Services cop, was killed shortly after 11 am after he pulled over a vehicle by a Mobil station on Jamaica Avenue near 241st Street that matched the description of a hit-and-run driver in Nassau County, sources said.

“The cop was walking toward the car. He got about five feet from the door and ‘bam:’ four shots,” said Paul Walcott, 40, a music producer. “Then he just peeled off and got on the highway. Two cars went chasing after him — not cops just regular people, witnesses.”

The man suspected of shooting Lopez was identified as Darrell Fuller and was taken in to custody on Tuesday night with a gunshot wound to the shoulder.

Fuller had four blown tires, so he ditched his ride and car-jacked another vehicle near Hempstead Avenue and the Cross Island Parkway, where he fatally shot the driver, sources said.

Fuller ditched that car near 114th Drive and 223rd Street and walked about a half mile.

An off-duty NYPD officer saw the perp and called in the description, but cops did not immediately respond, law-enforcement sources said.

Multiple special units were seen swarming the area in search of Fuller, including MTA, NYPD and Nassau County cops, as well as FBI agents.

MTA and NYPD cops in full riot gear were going door to door from Murdock to Hollis avenues between Francis Lewis and 112th Street. FBI agents and Nassau County cops were also on the scene.

A Nassau County helicopter was buzzing the neighborhood.

Lopez was taken to the New Hyde Park campus of North Shore Long Island Jewish hospital, where he was pronounced dead, sources said.

It was the second Nassau County police fatality in as many weeks.

Officer Joseph P. Olivieri, 43, was killed last week by a passing car while pulling over a vehicle near exit 35 in North Hills.

Lopez was unanimously adored by his neighbors in the tight knit Babylon community where he loved alone in a modest one story ranch.

Neighbor Mike Cullen, 51, said that Lopez knew Olivieri and was at his funeral just yesterday.

“We talked about Olivieri’s death on Saturday and what a loss it was,” Cullen said. “And a few days later we lose him. It’s just tragic.”

Originally from Queens, Lopez move to the Suffolk County neighborhood four years ago and made it a point to greet all newcomers to the area.

Colleen Donavan said Lopez brought her a pie when she moved in last year. “He couldn’t have been any nicer,” she said. “It’s just awful. He made me feel so welcome, I never forgot it.”

Lopez lived alone but was faithfully visited by his parents and sister as well as a girlfriend.

He was short but very muscular.

“He was a gym rat,” Cullen said. “He was like Hercules but the nicest guy in the world, always with a big smile on his face ready to help.”

He had recently bought a boat he called “Saltshaker” and was just beginning to enjoy taking it out.

Neighbor Dave Carter, 51, did Landscaping work for him. “I used to give him advice on the garden and just help him out from time to time. So one day he said ‘hey, Dave, you’re always doing stuff for me, let me do something for you. He gave me a card with his name on it, a PBA card. It’s says officer’s friend. This means a lot now.”

Additional reporting by Daniel Prendergast