I assume it was just a raid they conducted after their master died that went wrong as they didn't have voldemort to back them up.

 

Alastor Moody in his heyday, perhaps?

 

I think depending on the timing they may have tried the suicide by cop option and got captured instead, because we know that it was Bella and Crouch and her husband and his brother at least, all people we are told were Voldemort's most devoted. When they found out he was defeated they could have just given up on winning and decided to stay around and try to kill some Aurors rather than run like normal. Additionally I imagine that the Longbottoms had very decent wards(living with Augusta) so Bella may not have only come to the party with 4 but many more that just didnt survive the post torture fight.