A relative of a Queens man accused of fatally slashing his next-door neighbor’s throat says the suspect suffers from paranoid schizophrenia — and had been inexplicably fixated on the victim for years.
Dimitrios Manessis was arrested Tuesday night and charged with murder and weapon possession for the slaying of 75-year-old retired public school math teacher George Dourdounas earlier that day. The two men lived in adjacent apartments in Astoria.
“[The victim] never bothered him,” a family member of the suspect told the Daily News. “It was more like (Manessis’) mental illness kind of creating this issue, this invisible problem that wasn’t really there.”
Neighbors said Manessis, 48, had obsessively harassed the victim for years, including bizarrely accusing Dourdounasof not being authentically Greek.
Dourdounas’s throat was slashed just outside his first-floor apartment on 33rd St. near 28th Ave. about 1:40 p.m. Tuesday, cops said. The suspect lives in the apartment next door with his mother.
Manessis was diagnosed with schizophrenia a few years ago but had never been violent before, his relative said.
“He’s never shown any indications of this, so this is very surprising to us. He’s a very sweet person,” said the relative, who wished to remain anonymous.
“He did have some type of fixation with George. But it was spoken about with his social worker and his psychiatrist, so everyone was aware. And we tried to help him as much as we could. He would have good days too. He wouldn’t talk about him all the time. We don’t know what happened or what switched.”
A 55-year-old neighbor who asked to be named only as Ray said he had witnessed Manessis accosting the victim for years.
“He’d say, ‘You’re a fake Greek.’ He used a lot of expletives, ‘F’n this and F that. You’re no good. You’re not a Greek. You’re a fake Greek.’ I’d be standing right there,” said Ray.
“He’s very, very mentally ill. There’s obviously something very wrong but what can you do? I spoke to the landlord, I spoke to the neighbors. They said, ‘There’s nothing we could do. He hasn’t done anything wrong, so what can we do?’ And now this happened.”
Ray witnessed the suspect, who had retreated to his apartment, being taken into custody hours after the slaying
“I could hear the cops screaming, ‘Come out, come out!’” Ray said. “And he opened the door, he came out. They said, ‘Turn around! Walk backwards. Walk very slowly. Don’t move. Don’t move fast. Come out slowly.’”
Manessis’ family said the suspect had been doing everything he could to manage his mental illness— seeing a psychiatrist weekly and taking medication.
“This just sucks … If he didn’t have this [mental illness] he obviously wouldn’t do it,” she said. “He was a very, very sweet, funny guy. That’s really it. He had this [mental illness] that he couldn’t control. He could only control it to a certain point, as you see from yesterday.”
“Me and you don’t know how one would feel with those types of thoughts and feelings,” she added.

The relative said the good-natured victim brushed off Manessis’ past provocations.
“We knew George. He was very, very nice to us, despite how [Manessis] would talk to him. George treated us very nicely.”
Ray said Dourdounas was a retired high school math teacher who recently earned his PhD and was planning a return to academia as a college professor.
“He wanted to teach in college,” said the victim’s neighbor. “He said, ‘I got my PhD, and there’s no age limit for retirement and college teaching, so I can apply for college.’ And that’s what he did.”
“He never bothered anybody,” Ray added. “And he came home and he got killed.”
The suspect’s relative echoed that sentiment.
“We are very deeply sorry for the loss of him, and for his family,” she said. “He was our neighbor. We were cordial and kind. It’s just sad. It’s really sad on both parts. We don’t want this to happen at all.”