[wideawake]

Correct. It makes no sense that someone who legally purchased weapons and planned on dying while using them would file down the serial numbers.

Someone only does that if they want to sell them illegally to a third party and mask their provenance.

Filing them down could only create an added risk that he would be prevented from carrying out his evil plan - it wouldn't help him at all.

[Tall_Texan]

Correct. It makes no sense that someone who legally purchased weapons and planned on dying while using them would file down the serial numbers.

Agreed but maybe he wasn't planning on dying when he bought the guns and filed the serial numbers. Maybe he first planned on killing the girlfriend and getting away with it then changed his plans sometime between the purchase of the two guns and the execution of the crimes.