You and Ace got assigned together in a case. You were his secondary, albeit if he were the secondary he'd take charge as a primary immediately. He just wanted to make sure the case was done perfectly.

"Well, I think I know what killed this guy." He'd say, the two of you looking down at the dead, 350 pound man on the floor of the apartment. "I'm surprised the floor didn't collapse beneath him. You ask the wife a few questions and I'll check the rooms for anything."