[Of course he won't let go, even as his free hand reaches out to grab the statue. His head is reminding him that they're hanging off of priceless artwork, pieces that couldn't be replicated by modern standards if damaged. He's definitely not thinking straight because of the time, but at the same time he keeps this knowledge in mind - any damage could cost him his job more than losing the diamond would.

Jack can shake all he wants, his hand isn't removing itself from his arm. The detective would make to grab for his handcuffs but his free hand is currently occupied by grappling for purchase on the statue, blunt nails finding chips in the marble as he looks at the thief. From what he knows about the thief's escapades, he's always done things like this, usually the cop in question too much of a bumbling idiot to actually manage to catch him.]

If you didn't want to hurt anyone, you wouldn't be doing this in the first place.

[His voice is oddly calm for someone so high up off the ground. Hiccup finally manages to grab a foothold on the other shoulder of the statue, his prosthetic leg working against him for most of it, trouser leg riding up to expose the metal.]

I would've known it was you eventually. Your little signature's hard to miss if you know where to look.