A knife with what appeared to be fresh blood on it was found in the living room of homicide victim Joel A. Marino, according to court documents filed Wednesday.
Madison Police Department public information officer Joel DeSpain said police also recovered a white stocking cap with a red 'W' on the front and a gray, new-looking backpack.
Police believe the hat and backpack were likely in the possession of the 'person of interest' that is being sought in connection with the crime. DeSpain said the person likely discarded the items shortly after the attack on Marino occurred.
The knife, cap, backpack and other items found in the home are being taken to the Wisconsin State Crime Laboratory for forensic testing, according to DeSpain. He said police do not know if the recovered knife is the murder weapon.
Police are investigating the possibility that the backpack was stolen from a student union or library on UW-Madison's campus. DeSpain said students should be aware that the crime scene is close to the downtown area.
Its possible this person of interest was walking in the downtown campus area prior to this attack,"" he said.
DeSpain encouraged any students missing a backpack like the one found to contact the MPD. Police said they cannot rule out the homicide as a random crime at this point in the investigation.
""There's certainly nothing in Joel Marino's background that he did anything that would have led to him being a victim like this,"" DeSpain said.
Marino, a 31-year-old Madison resident, was found wounded in an alley on South Park Street Monday. Police said he was taken to a local hospital where he was pronounced dead.
Results of an autopsy showed Marino died of ""multiple penetrating wounds from a sharp instrument,"" Dane County Coroner John Stanley announced at a Tuesday news conference.
Marino's family, friends and coworkers have set up a reward fund for information leading to his arrest.