The FA will write to Manchester City after blue flares were set alight and thrown by home fans during last weekend’s defeat by Manchester United at the Etihad.
It’s unlikely that City will be punished over the incident, but the FA are keen to work with the club and Greater Manchester Police to identify the culprits who face a ban and criminal prosecution.
Meanwhile, City have escaped action over allegations that a coin was aimed at Jose Mourinho towards the end of United’s 3-2 win.