They were mainly just following the orders of those above and they were not the root of the problem.
If the order no longer came for them to pursue her then they would no longer have a reason to think about her ever again.
They would be too busy worrying about the damage she had done to their gang and the state it would be left in to think about anything related to her.
After everything had taken place and time had passed after they were busy dealing with the aftermath, the last thing they would think about was her.
Her involvement would probably be the last thing that they would ever think to connect her to anything that happened.
Without solid leadership in place, it was more likely that the gang itself would be torn apart by internal problems.
If that did not put a complete end to them then there were always other reasons why they would be unable to hold their gang together.