Team control foul question
 

A1 is dribbling at full speed towards the basket. At about the free throw line B1 cleanly slaps the ball away from behind and it goes directly into the hands of B2 who is positioned near the basket. Meanwhile B3 had established legal guarding position and A1, unable to stop, crashes into B3. B2 was in possession of the ball at the time of the contact. Is this a team control foul or not?

If B had the ball and A committed a foul, how could that possibly be a TC foul?

Based on your words in the OP, Team B is now in control, so no. Maybe if the loose ball and contact were very close together, and B3 bobbled, but even then, if B3 had control at any point short of contact, then it's a defensive foul on A1

Go over when team control is gained and lost.

It's a foul. Just not a TC foul.

Thanks. I wasn't sure if the other team actually had the ball at the time of the contact so we didn't shoot free throws. But it just got me to thinking about it so I posted this as a what if. I don't think I've ever had it happen before and it was very bang-bang.

Just be strong with whatever call you go with. If you decided there was team control, then be strong with that call and don't back down saying something like "I may have been wrong".

I made that mistake, as you can see in a recent thread I made "Should We Fix It?"

Good point. I was strong on the fact that I wasn't sure. :)

I think you made the right choice, given that you weren't sure if the other team had the ball -- benefit of the doubt to TC foul here.

I don't think there's anything wrong with getting help from a partner after making this call to make sure you have the right call. I've gone to a partner after they made a call on a member of the team in control as he was about to go shoot free throws for bonus and asked who was in team control when the foul happened. Once he realized the situation, we went with OOB instead of free throws.

If, in this situation, if I were unsure whether or not B2 had established player control (thus establishing team control for B) prior to the foul, I would err on the side of deciding that team control still belonged to A. My partner(s) may have useful information in making this decision. If it's clear that B2 had established player control prior to the foul, then this is not a team-control foul.