The ex-con accused of slitting a French tourist’s throat in a random attack in Harlem is a neighborhood “neck slasher” who’s ducked justice at least twice — infuriating one of his alleged victims, The Post has learned.

Khalief Young — who is charged in Friday’s horrific attack on Gabriel Bascou — was busted in June for a Harlem deli slashing, and in October for allegedly pummeling a woman inside his apartment building, according to police sources and court records obtained by The Post.

The first case is closed and sealed, and Young was cut loose without bail in the second, which is ongoing.

“If the law did what they should have done a year ago and they would have handed him the punishment he deserved maybe he wouldn’t have had the opportunity to do it again,” said Benjamin Onwudiwe, the alleged victim in the earlier attack.

Young, 28, allegedly ran up behind Onwudiwe and cut his neck on May 22 inside the 2278 Deli & Grocery on the corner of Adam Clayton Powell Jr. Blvd and West 134th Street, sources said.

The 58-year-old pharmacist said his attacker, “was talking to the people in the store, and when he [was] getting ready to leave the store, all of a sudden, I was stabbed in the back.”

“I thought he cut me with his nail but then blood started gushing out and that’s when I realized I was stabbed.”

Onwudiwe said he never caught sight of his attacker, adding “no words were exchanged, nothing.”

He said he was left with two scars on his neck as a result of the attack.

“If it had went down a little bit more deep I wouldn’t be here talking,” said Onwudiwe, who works at Heritage Pharmacy & Surgical Supplies.

Police arrested Young and charged him with assault on June 27, sources said.

But Onwudiwe said that, after that, “nothing happened.”

“I was going back and forth with the District Attorney’s office but they never did anything.”

“All the district attorney told me [was] nothing could be done and [he] told me not to go back to that store and that’s how they ended the case,” he added.

“This time he stabbed a white guy — now everyone is interested.”

The Manhattan DA’s office refused to comment on the case.

Onwudiwe said he didn’t want to identify a suspect to cops from a photo lineup since he “never saw his face.”

But a worker at the deli on Tuesday recognized Young as the alleged attacker and said he has a history of random slashings.

“He comes in here and if you look at him he’ll say to you ‘what are you looking at?’ and if you let down your guard he comes over and cuts you,” said Anthony Pena, 40, a cook at the deli.

“He goes up and down the block always getting into trouble,” said Pena, adding “he’s cut three people like that, behind the neck.”

A police source said of Young: “He’s a neck slasher.”

Jesus Ventura, 60, the super at Young’s building, called him a “very complicated person.”

Young spent nearly two years in state prison on weapons and drugs charges and was released on parole in April 2017.

“He’s had a lot of problems with multiple people in this building many have moved because of him,” said Ventura.

Then, in October, Young was allowed to hit the streets after being busted for allegedly pummeling a woman inside his Harlem apartment building.

Prosecutors requested Young, who was charged with assault, be held on $1,500 bail for allegedly punching the woman in the face and repeatedly kicking her — but Manhattan Criminal Court Judge Anne Swern released him.

Courts spokesman Lucien Chalfen, blamed New York’s bail reform laws, which took effect on Jan. 1, for the ruling.

“Had the Judge set bail, [Young] would have been released from jail on that date,” Chalfen said in a statement. “The judge was being both pragmatic and prescient.”

Swern also issued a temporary order of protection barring Young from contact with the victim, records show.

A few months later, Young would be busted again, this time for randomly cutting Bascou, a Parisian photographer, in the neck and face on Friday outside an IHOP down the block from the deli.

He was finally held without bail at his arraignment early Monday on charges of attempted murder in the second-degree and first-degree assault.

His next court date in that case is set for Friday.

Additional reporting by Rebecca Rosenberg, Natalie Musumeci and Tamar Lapin