How to make a long spy & fry work?

[GM Chyro]

Ok, i've hear and read about the scry&fry.

But there's something in my campaign i'd really like to work.

A situation: bbeg of the chapter sends out a couple of men to attack the party. He uses scry on the leader of his henchmen, should they fail he wants to cover up any leads back to him right?

Part 2 of the guy's method:
Should these henchmen fail, bbeg wants a way to incinerate the guy. By incinerate, he's not that uber-high a level, but bursting into flames.
Something which can be activated over a longer distance. Think something like a remote bomb going off by pressing a button.

Here's the example Look at 5:55

[cnetarian]

a variant of the contingency spell with a remote activation trigger. subject to the GM's discretion such a spell can be researched by the BBEG and then either placed on the henchman or on some items carried by the henchman.