One of the delights of a show like The Punisher being part of a grander, interconnected narrative over multiple series is the evolution of certain characters. While the leads usually don't evolve much beyond what the plot demands, side characters who start off in relatively low-level roles can quietly have their own arcs. Take the lead detective in the Billy Russo case. Who is Detective Mahoney on The Punisher? He should look familiar — he's only been in all three seasons of Daredevil and turned up in Jessica Jones as well. Warning: Spoilers for The Punisher Season 2 follow.
Fans first met Brett Mahoney back when he was just a regular police officer who hailed from Hell's Kitchen. He was in the premiere episode, and then spent a decent chunk of the back half of Daredevil Season 1 helping Nelson and Murdock take down Wilson Fisk, aka Kingpin. But it wasn't until Season 2, when Mahoney scored the Frank Castle collar, where he started getting promoted for his hard work. The Castle case was instrumental in helping Mahoney make the jump to the Detective side of the precinct.
That being said, Mahoney was barely in The Punisher Season 1, only turning up in Episode 10. This all changed this season, as Mahoney is in charge of the Billy Russo case, and his prisoner has escaped from the hospital.
But Mahoney's problem is less about Russo, who he's sure will turn up and be brought back in. It's Madani, who has been a thorn in his side since Day One. The Homeland security officer is obsessed with Russo, having humiliated herself to cover up Castle's involvement in the case. Even after Mahoney tries to ban her from Russo's hospital room, she's sliding in, scooping up evidence, and generally refusing to be forthcoming. Mahoney knows she must have some sort of source though, because every lead he follows, she's already there.
Mahoney's search into the truth of the Russo case turns up the idea that Madani lied in her statement of what occurred in The Punisher Season 1 finale. Putting two and two together, he realizes Castle was involved the whole time and still may be involved now.
The Punisher, both as a show and as a character, isn't one for subtlety. When Madani realizes Frank is going to go after Russo in broad daylight, she warns Mahoney in hopes he gets to Russo first. By the end of the incident, Mahoney winds up with two quarries. Russo, and his gang of ex-soldiers gone bad, and Frank Castle, who has apparently been co-opted and cared for by Homeland Security somehow and is now on the loose again.
Despite everything Madani says about Frank's "code," Mahoney isn't hearing it. He's frustrated she won't share with him, and when he tried to force her to talk, she shuts him down as a mere "New York City cop." Even a plea or two from Daredevil's Karen Page (Deborah Ann Wohl, in a small but vital guest-starring turn) does no good. Mahoney is determined to have both men locked up behind bars before the end of the season.