The Football Association are awaiting referee Andre Marriner's report into Manchester City midfielder Joey Barton's shorts-dropping antics.
Disciplinary chiefs will consider Marriner's version of the incident — which was drawn to his attention by police — before deciding whether or not action should be taken.
The 24-year-old midfielder bared his buttocks in the direction of Everton fans as he walked off the pitch at the end of Saturday's 1-1 Barclays Premiership draw at Goodison Park.
A spokesman for Merseyside Police said: "I can confirm that we are investigating this incident. We are currently gathering evidence.
"The matter was reported to the referee, who included it in his post-match report."
Barton's actions came as he was taunted by the home fans, and although keeper Nicky Weaver tried to stop him, he carried on.
It is the latest in a series of controversies to hit the midfielder, who signed a new four-year contract during the summer.