Costigan's mouth tightens as he listens to Bruce and an idea he's not entirely certain the other man will approve of crosses his mind. Perhaps it's a testament to his time undercover that it even enters his thoughts as an option. Regardless of agreement or disagreement, however, he trusts the other man not to dismiss it without proper reason and not to think less of him for simply suggesting it. So, after a beat, he replies.

"Maybe we don't need to ask." His eyes flash up to Bruce's, a sort of silent test to see if he should continue. He's not suggesting to kill one of them, but to maybe rough them up or knock them out and steal a sample of their DNA. It's the kind of thing having a scientist on your side comes in handy for.

To the latter, he takes another sip of his beer. Magic again. "Yeah, I saw it." A beat. "I asked Sabriel to help me look into it. She can teach magic, apparently, and knows a lot about the stuff. Doesn't do death magic herself, but knows about it. Even if it doesn't work the same here, she'll sure as hell know a lot more than me."

Costigan takes another swig of his drink. Anyone who knows him well enough will understand how important that means that he's taking the issue. Just getting the Bostonian to acknowledge magic is hard enough, let alone to ask for help from someone who uses it. Or to ask for help in general from someone outside his small circle.