Plot summary
Don and the team reopen a cold case when a bunch of kids playing in an abandoned empty construction site discover a police badge. When Charlie joins the investigation, they attempt to track down the owner of the badge, a police officer who has been missing for seventeen years but when the team discover that the dead cop was on his way to Internal Affairs, the investigation takes a turn. Meanwhile, Alan is informed that he's being sued. Lance Reddick and Hassan Johnson guest star; Will Patton makes another appearance as LAPD officer Lt. Gary Walker. Mathematics used: Laser Swath Mapping and quantum mechanics
Credits
Adapted from Wikipedia contributors, Numbers season 3. HTML formatting and reference markers removed.