Police are investigating reports of racist behaviour directed towards Everton's football players on the pitch during Carlisle's FA Cup fourth round tie.
The alleged incident happened following Everton's first goal in the match - scored by their Ivorian striker Arouna Koné.
Officers want anyone at Carlisle's ground to get in touch with them if they heard any racist remarks.
The club has also confirmed that it will conduct its own investigation and will punish any supporters who are found to have made racist comments.
"We are investigating allegations of racist behaviour directed towards Everton players following the first goal.
"Hate crime will not be tolerated in this county and any allegation will be fully investigated.
"We ask that anyone with information makes contact with police."
Full time whistle and Carlisle are out of the FA Cup having been beaten at home by Everton. Final score Carlisle United 0-3 Everton.
Everton's Ross Barkley strike makes it three for the visitors at Brunton Park
Carlisle United are through to the FA Cup Fourth Round after a dramatic penalty shootout win over fellow League Two club Yeovil Town.
In a Third Round Replay at Huish Park, Jack Compton put the home side in front in the first-half but the Cumbrians equalised through Antony Sweeney in the 79th minute.
Dramatically, former Carlisle striker Francois Zoko earned Yeovil a penalty in added time but fired his spot kick wide of the post.
Both sides were reduced to ten men in extra time, before Carlisle won 5-4 on penalties.
That result earned Keith Curle's side a home tie with Premier League side Everton in the Fourth Round.
Carlisle United will have to replay their FA Cup third round match after a 90th minute equaliser by Yeovil.
The Blues were twice in the lead against the football league's second bottom club.
Grainger scored first after 25 minutes and Carlisle held onto that lead until the 71st minute when their former player, Francois Zoko, put Yeovil level.
Ellis put Carlisle back in the lead and heading for a fourth round place but Jeffers equalised for Yeovil in stoppage time.
If Carlisle can win the replay it will be their first time in the fourth round for almost 20 years.
Manager Graham Kavanagh had said that he wanted a tie against a Premier League club, and he has got one. Carlisle United and their supporters will make the short trip into the North East to the Stadium of Light to face Sunderland between the 3-6 January
James Berrett put Carlisle United on their way into the third round with this fabulous right footed strike.