Castleford have released a statement requesting information after a flare was thrown on to the pitch during the Tigers’ defeat to Salford last Thursday.
The incident occurred in the second half and TV cameras appeared to identify the perpetrator after fellow visiting supporters reacted angrily to the incident.
The club has confirmed it is under investigation by the RFL for a possible breach of operational rules “regarding the conduct of the crowd at the AJ Bell Stadium and the Halliwell Jones Stadium in recent play-off fixtures against Salford and Warrington”.
They are now seeking to formally identify those responsible.
The statement adds: “Following the release of CCTV images from the clash against the Red Devils, the club is taking steps to identify those supporters it wishes to speak to about the incident last Thursday evening, which led to a fan requiring medical attention.
“Anybody with relevant information can contact the club in strictest confidence by emailing email@example.com.”
The announcement comes after the club emphasised a “zero-tolerance” approach to anybody caught using incendiary devices such as smoke bombs, fireworks and flares at matches.
The statement closes by thanking “the vast majority of fans for their continued support of Castleford Tigers throughout 2019 and their impeccable behaviour on match days”.