Will ANG Security Forces tech school be condensed for someone who is NG Infantry and has a law enforcement background?

I was ARNG infantry and state law enforcement. You'll go through the full tech school, and you'll need it. The procedures are different, yet similar.

Although I have been out for 8 years and things do change. However, you are going from Army National Guard (Army Trained) to Air National Guard (Air Force Trained). I would bet you will have to go through the full training.

Maybe. Once upon a time, various AF Technical Training schools would permit a "test-out" option for certain blocks of training. I DO NOT know if Security Forces does that or not. As your recruiter is not sure, you might reach out to the SF school house and ask them if there points where someone with LE experience might be able to test out. The worst they can say is no. I'll see if I can find a number for the school house when I get to work this week. PM me in a couple of days if you don't hear anything.