A 75-year-old retired math teacher was fatally stabbed in his New York City apartment by a neighbor, according to police reports and witness accounts.

Neighbors identified the victim and said the alleged attacker was Dimitrios Manessis, who lived next door to the elderly man. According to residents of the building, the two men had ongoing disputes.

Witnesses described the incident as occurring when the teacher returned home, where he was allegedly attacked and killed by his neighbor. Local residents reported that Manessis had what they characterized as an unusual fixation on the victim.

Neighbors said the situation had been building over time before culminating in the deadly attack. The incident occurred inside the apartment building where both men lived.

Police are investigating the stabbing death. No additional details about charges or the investigation have been released by authorities at this time.