Leeds United were forced to evacuate Elland Road on Friday after a security threat was made towards the club.
West Yorkshire Police arrested a 42-year-old man in connection with the incident, which led to staff being sent home from the stadium and the club shop closed.
Sportsmail understands the threat was made by a user on social media and reported to police on Thursday night.
Officers then opened an investigation to 'establish the credibility of the threat' and visited Elland Road on Friday morning to check if the ground was safe.
West Yorkshire Police said in a statement: 'Police were called to attend Elland Road football stadium following reports of a security threat to the premises.