Ottawa police are continuing to look for clues and possible witnesses in the city's seventh murder of the year after investigators upgraded the suspicious death of an Ottawa man to a homicide case on Monday.

Police say Sean Murphy, 51, was found unconscious and critically injured lying beside his bike near a Mac's Milk convenience store at the corner of Merivale Road and Shillington Avenue shortly after leaving an area bar on Aug. 26. He died of his injuries on Sept. 16.

"Sean, he was a very mellow, mellow guy. He wouldn't hurt a fly," said friend Bob Gagnon.

Although police originally pegged the case an accident, officers announced Monday they now consider Murphy's death a homicide.

Murphy's friends, meanwhile, say they don't understand why it took so long for police to determine their friend was a victim of murder.

"When it comes to somebody like that, that nobody sort of cares about except us . . . it's too bad," said Gagnon.

Investigators are continuing to look for witnesses in the case and ask anyone with information to contact Ottawa police at 613-236-1222 ext. 5493 or Crime Stoppers at 613-233-TIPS.

With a report from CTV Ottawa's Catherine Lathem