Are opposing figures blocking terrain?
No? Then it should be fine assuming the other requirements (within range and LoF) are met.

Really? I'd think you wouldn't be able to because stealthed units block line of fire, so wouldn't the closest you could put a timebomb to a stealthed unit be a square adjacent to it?

A character never blocks the LoF to the square it occupies.

Also, Stealth only blocks LoF to the character.

No kidding. Well, that certainly changes things for my Tabby strategies. Thanks!