Trace Gallagher just spoke with James Usera, former friend of accused cop killer Christopher Dorner. Usera was mentioned in Dorner's manifesto, which surfaced online last week after the manhunt

for Dorner began.

Police exchanged fire with Dorner earlier today along a mountain road in Big Bear, California, where Dorner's burned-out truck was found last week. Two officers were injured in the firefight and now, Dorner is holed up in a cabin, exchanging fire with police who are surrounding him.

Usera issued a plea to Dorner to surrender, but said the whole situation has surprised him based on the friendship he had with Dorner in college.

Watch the interview with Usera below, and click here for live updates on the standoff.