How would you handle this - Fire involved.....?

Here's my problem: My son plays with some neighborhood boys - 2 of them are brothers - 8 yr old and 13 yr old. My son is 9 and hangs with the 13 yr old because they have more in common and the 8 yr old is really annoying - Yesterday they were all coming over to my house to cut the lawn - my son came home first - and told the 8 yr old to stay at the corner to wait for his brother - the 13 yr old... as I was leaving my driveway - the 8 yr old comes running and screams - there's a fire in the woods... so I drove down, and sure enough - there was so I called 911.

My son didn't light it - but he thinks the 8 yr old did. The 8 yr old has only fessed up to "seeing a spark in the woods, and blowing on it" - now
#1- my son didn't see the fire when he passed that way not more than 3 mins earlier
#2- the 8 yr old is fascinated by fire.
#3 my son and the 13yr old has caught the 8 yr old lighting a leaf on a separate date.
Would you talk to the kids parents - or let the school handle it?

no one saw him do it, but my son is convinced he did. My son told his teacher in school about the fire, and the social worker who knows this 8 yr old and his problems is now involved.

Should I just let the school handle this, or should I approach the parents - who I only know as neighborhood people - not personally, or socially.

My son is freaked out, and thinks the kid may do it again since he didn't get in any trouble for it. Thanks for your time!!

Let the social worker handle it and let your son know that he should feel like he can always continue to come to you with anything that worries him. Tell him that the people who need to be told were told and that he will hopefully get the help he needs.

Let the parents know, but not in a way that makes it "my kid said your kid did this" type of way or they will become defensive.
I just took a psychology class and one of the four detections that someone will become a violent adult is fire setting. Just thought you should know...
Scary.

Call the fire dept and tell them of your suspicions. They will know how to handle it.

I would make sure your son knows the consequences of playing with fire and try to help him find new friends.

Let the social worker handle it.