Point lights flashing as the good doctor mentioned would do the trick.

If you want a really dramatic animaed effect you can use spot lights and rotate them alternately, like when one is at y rotate 0 position, another is at y rotate 90. 

Actually I would parent them to the physical light objects and rotate those physical objects for the proper look.

The moving shadows produced can give an added dramatic effect to a crime scene animation for example.

Hey! His nose is dry! ... Someone should lick it,  just in case. - Diego