He deliberately misstated civilian casualties, and in the case of the F-15 that took out a civilian train, Clark had the film of the incident altered to make it look like an accident, then when discovered, he blamed the bombing on the pilot, who was only following orders to hit that target.
The drip-drip of information on Clark will become a steady stream should he do well in NH. I suspect he wont, and most of the dirt on Clark will not come out until much later.