A man was found dead in the street on Christmas Day.
Emergency services were called to Cardigan Street in Luton at about 07:30 GMT but the man, in his 50s, was pronounced dead at the scene.
Police said the death was being treated as unexplained and appealed for anyone with information to get in touch.
Det Insp Dani Bailey said: "We are working to piece together the circumstances around this tragic incident."
"We would particularly like to hear from anyone who has CCTV or dashcam footage of the area from the morning, as well as anyone who was in the area at the time or has any other relevant information.
"The fact a man has lost his life on Christmas Day is especially poignant."