Tony DeGiusti also said that at least six people heard gunshots and others saw a fight in a parking lot.
But no one called police, not even the person who reports walking by Reed's body, the chief said.
Police are offering $5,000 for clues to the killer's identity and say they're looking for anyone who attended a party at the off-campus University Green apartments where he was found dead.
The 20-year-old communications major from Chicago was shot multiple times Friday in what police say may have been a robbery.
So far, about 30 people have been interviewed by police, multiple pieces of evidence have been collected and several homes have been searched, MLive.com reported.
"We are actively working some solid leads," DeGiusti said. "We are diligently working on this case."
There have also been several attacks near campus in recent days, including sexual assaults.
"This has been an extremely bizarre and unusual series of events these past few days with senseless, random acts of violence," said university President Sue Martin.
Teammates plan to attend Reed's funeral Saturday in Harvey, Ill. A visitation is scheduled for Friday.
The 5-foot-10, 161-pound Reed played in six games this season, catching 15 passes for 181 yards and a touchdown. He made 18 receptions for 171 yards and scored a touchdown in nine games last season.
A moment of silence was held for Reed before Saturday's home game against Ohio, and team captains led the team out of the locker room holding his No. 2 jersey aloft. Players wore helmet decals and jersey patches with Reed's number on them.
Investigation updates: http://www.emich.edu/community-notice