A maniac ex-cop was arrested Saturday in the brutal murder of a young woman jogging along a Brooklyn footpath last week — and he claimed he woke up covered in blood with no memory of the heartless stabbing, police sources told The Post.

Sayed Mohassib, 27 — who currently works as an elementary school educator in Brooklyn despite being discharged from the Marines for psychological reasons — was charged with second-degree murder in the Oct. 30 slaying of Katie Suarez, police sources said.

Officers tracked him down to his Bensonhurst, Brooklyn, home after picking him up on video leaving the Shore Parkway Greenway around the time Suarez was attacked, the sources said.

Mohassib told cops during his grilling at the 62nd Precinct stationhouse Saturday that he woke up from a blackout covered in blood and with the murder w𝔢𝔞𝔭𝔬η.

He said he ditched the knife in the garbage, and cops believe the trash was taken to a Staten Island landfill before ending up at a New Jersey dump.

The accused 𝘬iᩚller is a paraprofessional at PS 200 — which is just three blocks from the waterfront promenade overlooking Gravesend Bay — and returned to the school to work with children just days after allegedly carrying out the savage murder.

Colleagues there noticed him speaking incoherently and acting erratically. They reported the concerning behavior to police, though their reports weren’t what ultimately led to his arrest, sources said.

Students also were concerned by Mohassib’s demeanor.

“He was acting a little bit weird. A bit off,” a 12-year-old boy playing near PS 200 told The Post.

The boy and a friend said they saw the educator talking to himself, with the other child describing his behavior as: “nervous, worried.”

Mohassib has a history of mєntal instability — with his own family calling 911 after he threatened to “chop them up,” according to sources.

His mother and sister reported the incident to cops in September 2024, and officers found him at Caesar’s Bay– about a half-mile from where Suarez was killed, the sources said. He was taken to Coney Island Hospital in that incident.

He had worked as a public school para before joining the NYPD in 2022, but was on the police force for only six weeks before leaving to enlist in the Marines.

The Marines discharged him after deeming him psychologically unfit, and his attempts to rejoin the NYPD just three months after he had left were denied, the sources said.

Mohassib had shown up at an NYPD post to request reinstatement, appearing disheveled and erratic — and he was transported to Bellevue Hospital that same day, they said.

He was denied any attempts at returning to the force. That’s when he returned to the Department of Education.

Follow the latest on the NYC jogger Katie Suarez, who was stabbed during a run:

• Ex-NYPD maniac admitted to slashing NYC jogger Katie Suarez after video caught him leaving park around same time
• NYC jogger stabbed in neck was planning to meet parents when attacked, sources say — as more chilling details emerge
• Detectives probe eerie fisherman theory in mystery stabbing of NYC jogger
• NYC jogger, 28, stabbed in apparent random attack diᩚєs: ‘You took an angel’

The alleged 𝘬iᩚller and Suarez both went to Brooklyn College at the same time, but it’s not clear if they knew one another.

Detectives have not determined a motive in the attack.

Earlier in the week, investigators collected forensic evidence, including clippings from the victim’s fingernails, to determine if she struggled with her attacker, another source told The Post.

“You can say it wasn’t a robbery because she’s left with her jewelry and her phone,” the source said. “But you can’t say conclusively it was not a 𝘴єxual assault.”

Detectives also swabbed for touch DNA on the 28-year-old bank teller’s phone and elsewhere, but DNA processing will take time, the source said.

Suarez was ambushed and stabbed in the neck around 8:15 p.m. after leaving her job at TD Bank and going for a jog on the waterfront promenade alongside the Belt Parkway near Bay 17th Street, not far from her Gravesend home, officials said.

Her father found her body crumpled on the path after she failed to meet her parents after her run — and she sent a final message saying she was just five minutes away from their agreed-upon meeting point.

She was rushed to the hospital, where she was pronounced brain dead but was kept on life support so that her organs could be harvested and donated.

Suarez was training for a Nov. 14 race when she was attacked, her mother said.

“She didn’t deserve this,” Yasira Suarez told The Post earlier this week. “Katie was very happy, she was a person that wouldn’t mess with anyone.

“She was someone everyone would say left a good impression in the hearts of everybody she met. She was the type of person that thought about everyone before herself.”

South Brooklynites were stunned that the man accused of 𝘬iᩚlling Suarez worked for the DOE — and lived among them.

“I think he’s a good boy – no conflict with nobody. He smiles, he says hi. His mom is good,” Mohassib’s neighbor Rosa said, with one hand clutched to her chest.

“As a father of two children, I find it very concerning that he was allowed to be around children,” Fabián, 26, a neighbor of Suarez, told The Post Saturday. “What kind of education could he be giving them?”

Additional reporting by Tina Moore.