Hamilton police say they are investigating the suspicious death of a 54-year-old man in the Waterdown neighbourhood earlier this week.Officers say the man was found unresponsive on the sidewalk near the Dundas Street East and 1st Street area just after 6:20 p.m. on Sept. 7.The man was transported to hospital, and later pronounced deceased, according to police.Investigators say at the time, the death was not considered suspicious. However, in the days that followed, investigators reviewed video footage, spoke with witnesses and received additional information from a post-mortem examination. Police say the information that emerged raised concerns about the circumstances surrounding the man’s death.“The death is now being investigated as suspicious and the Hamilton Police Homicide Unit has assumed carriage of the investigation. At this time, the death has not been classified as a homicide,” police wrote in a media release Friday.Detectives are asking residents, businesses and motorists in the area to review security, doorbell and dash camera footage from the evening of Sept. 7 . Anyone with information or video that may assist investigators is asked to contact police or Crime Stoppers.