A man was found dead with lacerations to his head and in a pool of his own blood at his Upper East Side home in a mysterious killing, police sources said.

Just after 4 p.m. Wednesday, police received a call about a man who was discovered dead inside his apartment on East 83rd Street, police said. Investigators are treating the man's death as suspicious, and police sources said the victim had injuries to his head that did not seem to match a fall or accident.

The victim has only been identified as a 64-year-old man named Kenny, who exercised daily and was beloved by neighbors, according to a man who lived in the building and knew the victim for a decade.

"When we would see each other ... he would always wave, [saying] 'have a nice evening — good night, Charlie,” said neighbor Charles Franck. "That’s the kind of guy he was."

Crime scene investigators were still collecting evidence late Wednesday night, and police said their investigation is in its very early stages.