word choice - Is this use of 'whom' appropriate or should I reword the sentence?

May I ask if the following sentence sounds right or if I would be better off rewriting it?

Stockpiles of weapons were found in the building of the staff members who worked there - one of whom was later caught attempting to smuggle some of the guns out in the boot of his car.

The part I'm particularly concerned about is the 'one of whom was later caught'. It doesn't seem to sit right with me for some reason; is there a better way to word it? I'm basically just trying to say that one member of a group got busted. Thank you.