Luton Town fans have been reported to the FA after their behaviour at Burton Albion on Saturday.
The game was stopped in the second half when Brewers goalkeeper Jon McLaughlin passed an object to referee James Adcock that appeared to have been thrown by the Hatters supporters.
A statement on the Luton official website said: “We are disappointed to inform you that in the wake of Saturday’s game at Burton, we have received a letter from the Football Association regarding their intention to conduct an investigation into missiles that were thrown on to the pitch during play.
“We are working closely with Burton Albion to find out who was responsible for this dangerous behaviour.
“CCTV coverage of the crowd is currently being sought to pinpoint those taking part in an act which Luton Town does not tolerate.
“In the event that any supporter of Luton Town Football Club is identified they will be banned from Kenilworth Road for six years.”
“As a club we were extremely proud to have taken such a vocal and compassionate following to the Pirelli Stadium.
“But if any Luton Town supporter is found to be responsible for the throwing of missiles, we cannot ignore the potential damage this could have caused.
“Such behaviour has no place in football, especially not at Kenilworth Road.”