Updated

Three people have been arrested in the fatal shooting last summer of a University of Michigan medical student who was also an Air Force officer, police said Thursday evening.

The suspects had no previous connection to victim Paul DeWolf or to the university, Ann Arbor police Chief John Seto said. He said charges weren't immediately filed Thursday but were expected.

Police haven't released the suspects' names.

DeWolf, 25, was found fatally shot at the off-campus Phi Rho Sigma medical fraternity July 24 after failing to appear for work at a hospital. He was a native of Schoolcraft in southwestern Michigan and a graduate of Grand Valley State University. He was attending medical school on an Air Force scholarship and held the rank of second lieutenant.

Hundreds of people turned out for his funeral. City and campus police had been offering at least $10,000 for information leading to identification of the culprits.

"Our focus continues to be the successful conclusion of this incident and respect for the DeWolf family," Seto said in a statement. "As the judicial process continues, we ask everyone's patience. Additional information will be released as soon as it's appropriate."

DeWolf's father, Thom DeWolf, told MLive.com that he was relieved to learn his son didn't know the suspects, even if the randomness of the killing was terrible.

"The fact that . it was nobody Paul knew, and no one we're going to know, that was huge," he said. "There's always the concern of: Who is it? Who did it? Is it someone we know?"

University President Mary Sue Coleman released a statement saying she hoped the arrests brought some relief to those who knew Paul DeWolf.

"We hope today's developments provide some solace to Paul DeWolf's family and friends, who remain in our thoughts," the statement said. "We will now join the greater Ann Arbor community in awaiting the outcome of the judicial process in this case."