MILWAUKEE - Nathan Potter, 21, was gunned down Monday morning about a block from his apartment. His family is still looking for answers.

It happened at Dousman and Wright in the Riverwest neighborhood.

Potter left behind so many people that loved him. Friday, hundreds came to pay their respects; but there's still no closure for his family.

They're asking anyone who knows anything about the shooting death of the University of Wisconsin Milwaukee senior to call police.

"I would like them to call my family and would appreciate it beyond all belief. We need to find who did this," says his younger brother, Nick.

Milwaukee police say Nathan's prior conviction for marijuana might have something to do with his death. His family doesn't believe it.

His best friend, Michael Garcia says, "I think this has to be random, there's no way they knew Nate Potter."

Nathan's girlfriend, Casandra Smith adds, "I think if there was trouble then the trouble happened that night right before it happened."

Potter was walking home alone and carrying a backpack when he was killed. Friends say he went home early to work for his dad the next morning.

Police were looking for a blue car that sped from the scene, but don't know if it's connected to the case.

His girlfriend says no one deserves to lose a loved one this way.

"There's someone out there that knows something. I'm just begging, pleading just to have some resolve to this. There's not a lot of closure we can get that would help find justice."

Milwaukee police are also asking anyone with information to come forward.