March is the head of Internal Affairs at the SBPD and called on by Lassiter and Juliet to help with Dan Cooper's murder case because they believe the person he was investigating might have had motive to kill him. March is unwilling to reveal any sensitive information due to their lack of evidence, but does inform the duo that Cooper's day-to-day work mostly included chasing paper trails and upholding professional standards, which makes him believe Cooper cannot have had any real enemies in the first place.
March's relationship with Lassiter is strained, to say the least. Lassiter's low opinion of Internal Affairs in general causes some friction, and March is not at all pleased with how Lassiter acts in certain situations. For example, he reveals that Lassiter discharged his weapon twice at a circus in 2004, and put an 86-year-old lady in full-body restraints in 2010.