Not sure what to do about child’s friend.

I have a 6yo daughter who is autistic and adhd, she started primary school this year and is at a small mainstream school. She has settled in okay, and knew quite a few kids from kinder and is overall quite popular. She has one friend however who I am not too sure about, this friend also has some behavioural issues although no formal diagnosis. The problem I’m having is that this friend openly encourages my child to defy myself or her dad, she does this infront of us as well. She will encourage her to run away at pick up time, and has even encouraged her to walk herself to school without us (which is a huge concern due to her difficulties with recognising danger and special awareness). There have also been other situations including trapping my child in her room during a play date so she couldn’t leave. I’m not sure how to approach this as some people have suggested I talk to the parents of this child but they are already well aware of her behaviour, but it makes me anxious as my child already has little to no impulse control and doesn’t need other children helping to influence her to make dangerous choices. I also don’t know if maybe I’m just over reacting and this is somewhat normal behaviour.