A guy once busted for randomly slashing a stranger is the suspected Brooklyn serial attacker who fatally stabbed an 83-year-old man — after the victim had just hit the lottery, cops and pals said Sunday.

The details surfaced as chilling revelations also emerged about the deadly assault, which was caught on surveillance video and includes the assailant kicking the beloved elderly man for good measure after stabbing him, police sources added to The Post.

Suspect Joevani Vale, 26, allegedly randomly first slugged a woman, slashed another female stranger and then followed and ambushed elderly Ramon Cintron — all in less than one horrific hour in Saturday’s Boerum Hill crime spree, cops said.

Police are now hunting for Vale.

“We were supposed to go visit [Cintron] on Friday, and he wasn’t feeling good, and he had to go into the hospital,” the tragic man’s nephew, Angel Cintron, told The Post, noting his uncle had a pacemaker. “He came out Saturday morning, and the first thing he did was go over and play his numbers at that corner deli.

“He always went to the corner to play the numbers. His whole life he did that.”

Two neighbors added to The Post on Sunday that Cintron scored in a game of chance before he was killed.

It was unclear how much money the victim may have won, but Angel said police told the family that Ramon’s wallet was missing, which “makes perfect sense” now.

“[A robbery is] the only reason somebody would hurt him. He was so kind to everyone,” Angel said of his slain uncle.

Cintron’s niece, Elisa, said Ramon — who was affectionately nicknamed “Flaco,” Spanish for “Skinny” — “was so full of life.

“He was very independent and genuinely a nice, happy, friendly person,” she said. “He worked at the same pharmacy until it went out of business. He worked into his 70s.”

She said her father, Ramon’s brother, “isn’t doing too well.

“He has a very tough job of telling everyone in the family what happened,” Elisa said. “He is taking it very hard. I’ve never seen him like this. No one would ever think that this is how Flaco would leave.”

The victim’s neighbors shared their affection for Ramon, too. 

“I love that old man like my grandfather,” Victor Santiago, the manager of Papa Firo Grocery in Boerum Hill, told The Post of Cintron on Sunday. “He comes every day at 5 [p.m.] and hangs out and plays the Lotto and the scratch-off. He does favors for everyone.

“He’s like a grandfather to the neighborhood,” Santiago said.

Vale has at least three prior arrests, including for slashing a stranger in Brooklyn in September 2020.

In that case, Vale was charged with criminal possession of a weapon, menacing and assault in the attack on a 36-year-old man in front of 502 President St. in Carroll Gardens.

Vale was previously charged with forcible touching in Brooklyn’s Crown Heights neighborhood in 2016 and public lewdness in the borough’s 84th Precinct, which includes Boerum Hill, in 2015.

He was identified in Ramon Cintron’s slaying from surveillance cameras in the area, according to police.

Vale and Cintron were neighbors — they both lived in the same building in the Wyckoff Gardens public housing complex.

Vale’s alleged violent spree began around 1 p.m., when he allegedly randomly slugged a 47-year-old woman at the intersection of Pacific Street and Third Avenue, police sources said.

Less than a half-hour later, he allegedly randomly slashed another woman, 31, in her leg in front of 134 Nevins St. before running off, cops said.

Shortly before 2 p.m., cops then found Cintron lying on his back in a pool of blood after he was stabbed to death in the elevator on the 19th floor of Wyckoff Houses — just steps from his apartment, according to police.

Surveillance cameras in the building allegedly show Vale entering the building around 1:30 p.m. and disappearing from view for about 11 minutes before he’s seen returning to the lobby in different clothes, sources said.

Shortly before 1:45 p.m. he then gets into the elevator with Cintron, with the two seen chatting before Vale allegedly whips out a knife and stabs the elderly victim in the neck, according to sources. 

Vale then allegedly kicks Cintron before he is seen running to the stairwell and fleeing the scene, sources said. 

The elevator goes up to the 21st floor, where Cintron’s foot keeps the door from closing, where a neighbor spotted him and called 911, the sources said. 

The elderly victim had slash wounds to his neck and right arm and was pronounced dead at the scene.

“Flaco, everybody loved him,” the neighbor said. “He had a lot of heart.

“He goes over to that grocery store, Papa Firo, every day and plays the number, and yesterday he was going to collect on a winner,” the friend said. “And he followed him.

“I stay away from him,” the neighbor said of Vale.

Additional reporting by Larry Celona and Steve Janoski