Police say they are investigating the death of a Brooklyn man as a homicide after city medical examiners determined he was killed.

NYPD officers discovered 51-year-old Justin Tetro unconscious with head and neck injuries while conducting a wellness check at his building on Pennsylvania Avenue and Fulton Street in Cypress Hills on Dec. 11, according to authorities. The following day, the city’s Office of the Chief Medical Examiner ruled his death a homicide.

Police said Tuesday they are still looking into the circumstances of Tetro’s killing and did not yet have a description of a possible suspect.

NYPD data shows there have been 13 homicides in the 75th Precinct, which includes East New York and Cypress Hills, through Dec. 14 this year, up one from the same date last year. Citywide, homicides are down more than 21%, per the data.

This is a developing story based on preliminary information from police and may be updated.