The Kansas City Chiefs&#8217; Jovan Belcher sits on the sidelines during the third quarter against the New York Jets  in East Rutherford, N.J., in 2011.
The Kansas City Chiefs' Jovan Belcher sits on the sidelines during the third quarter against the New York Jets in East Rutherford, N.J., in 2011. Police say Belcher fatally shot his girlfriend early Saturday, Dec. 1, 2012, in Kansas City, Mo., then drove to Arrowhead Stadium and committed suicide in front of his coach and general manager. (AP Photo/Kathy Willens, File)

GREEN BAY, Wis. -- At first, there was no name attached. He heard about the murder-suicide in Kansas City, but it wasn't until Saturday afternoon that Green Bay Packers rookie safety Jerron McMillian learned the NFL player involved was his former college teammate, Jovan Belcher.

For two years, McMillian and Belcher played together at Maine. When the news broke, McMillian called up former teammates.

Nobody could understand why.

"It was like, 'Did this really happen?' " McMillian said. "It's something you really have to face. You have to keep that in your mind and your heart."

Like the rest of the nation, McMillian was shocked to hear the Chiefs linebacker fatally shot his girlfriend and then took his own life at the Chiefs' facility. At Maine, the two had "a good friendship," McMillian said.

He described Belcher as someone who "used to tell me the funniest things." And on game day, he was all business. Throughout Green Bay's 23-14 win over the Minnesota Vikings on Sunday, Belcher was on McMillian's mind.

"I wanted to keep it in my mind and just come out here, get the job done and get a win for him," McMillian said. "I just played for him in my heart because that's part of me. He was a teammate, the Black Bears. We went to the same school. So it was big to come out here as a team and get a win."

Belcher never struck McMillian as someone who would do something like this.

"Sometimes, I just don't understand," he said.

The last time McMillian spoke to his former Black Bears teammate was when the Chiefs visited Green Bay for an exhibition game in August. The two caught up afterward and then McMillian called his old teammate back a few days later just to check in.

McMillian agreed that this tragedy shows that sometimes you never quite know what another player could be going through off the field.

"A lot of people outside of football don't really understand what players go through when they're not doing their job. You don't know what type of emotion or what they could be going through," he said. "It's always something outside of things that you don't really know about or don't have a clue. And then you do find out and it's like, 'Dang, only if I could have done something to help him.' "