Volume 10. "A corpse is a corpse/Of course, of course/And no-one can talk to a corpse, of course..."
"I'm not a geek! I'm a nerd! We're smarter!"
Earlier example, also from Numata: when Sasayama, er, "persuades" the Kurosagi crew to do some charity work at an old folk's home, he offers to use his corpse-dowsing ability to figure out who will die next. It works.
From Vol 6:
Sasayama: It isn't going to be one of those things where I'm going to open it, and there's going to be this woman inside with all her limbs cut off, but still alive?