Two men have been arrested after a man was found dead in the doorway of his home in Grimsby.
John Smith, 69, was discovered with serious knife wounds in Carnforth Crescent at about 06:40 BST on Sunday.
Humberside Police said the men, aged 31 and 56, were in custody to assist police with their inquiries.
The force said it was treating the death as unexplained and further forensic tests were being carried out "to confirm Mr Smith's lifestyle".
It has declined to give details of what the men have been arrested on suspicion of.
Det Ch Insp Wendy North said: "A major part of the ongoing investigation is focussed on understanding more about the lifestyle of John Smith, who we are hearing was a private, mild mannered man."
She appealed for anyone with information to come forward, in particular "details about his routines or the events of the days before he died".