A man is seriously ill in hospital after he was found collapsed with head injuries in an alleyway in Cambridgeshire.
Police are appealing for information on what had happened to the 46-year-old before a cyclist found him off the High Street, March, on Friday night.
The man was taken to Addenbrooke's Hospital with a serious, but not life-threatening, head injury, police said.
They would like two men seen in the area at about 2200 GMT to contact them.
It is believed the men may have information that could help the inquiry.
Det Con Colin Yendley said: "I would like to hear from anyone who was in the area at the time who may have information that could help our investigation.
"It is not clear what happened but we believe the victim may have been assaulted.
"I would also urge the cyclist who first reported the incident to police officers to contact me."