Detectives have appealed for a late night dog walker who may have information about a murder in Paisley at the weekend to come forward.
Craig McClelland, 31, died on Sunday after being found seriously injured in Tweed Avenue at about 23:20.
The male dog walker was seen in nearby Peacock Drive and Morar Drive a few minutes earlier.
Police also want to speak to people who were leaving several house parties going on in the area at the time.
Mr McClelland, who lived locally, was stabbed during an altercation on his way to a friend's home and police are treating his death as murder.
Det Supt Allan Burton said: "A young man has had his life violently taken from him, leaving young children without a father, a woman without her partner, and a family completely devastated.
"Somebody must know who is responsible for this evil and senseless crime and I would appeal to you to do the right thing and tell the police what you know."
The officer said the dog walker was seen at about 23:15 with a small, dark dog - possibly a West Highland Terrier - and appealed for the man to come forward.
He added: "We also understand that there were several house parties taking place in the surrounding area, with people leaving around the time Mr McClelland was attacked.
"If you were one of those people, it is absolutely vital that you get in touch with officers to establish whether you could be a potential witness.
"Whether you saw the attack or not, if you were in the area at the time, you may be able to help us piece together the circumstances leading up to and after the incident."