Medical Examiner's Ruling Sparks Murder Mystery On The Upper East Side

NEW YORK (CBSNewYork) -- A murder mystery was unfolding on the Upper East Side where authorities say an elderly man was strangled.

It's been more than a week since the man was found dead inside of his apartment.

His death has been considered a homicide, and police are searching for a suspect.

As CBS2's Emily Smith reported, the NYPD has investigators inside a posh Upper East Side building on 64th Street and Madison Ave, where Christopher Cooley was found dead in his apartment last week.

The NYPD initially believed that Cooley died from a medical issue, but the medical examiner ruled the 78-year-old's death a homicide.

Sources told CBS2 that Cooley's sister found him slumped over in his 11th floor apartment, after she hadn't heard from him in a while.

Neighbors who knew him hesitated to speak due to the alleged nature of his death.

"He was fine, he was fine," one said.

"A nice guy I think," another added.

Police said Cooley was found fully dressed with a tie oddly twisted around his neck. It's unclear if the apartment had been robbed, but Cooley had nearly $200 inside his pocket.

Aside from a broken lamp the home appeared to be in order, and the door was locked from the inside.

Cooley lived alone. His wife passed away a few years ago, and they never had any kids.

Sources told CBS2 Cooley had cancer, but it is unknown if it had anything to do with his death.

Police do not have any suspects, but are checking Cooley's computer for any information that might lead to one.