Manchester United intend to take action after a controversial chant, aimed towards Romelu Lukaku, rang around St. Mary's Stadium during United's 1-0 victory over Southampton on Saturday.
The Belgian striker, who has struck a rich vein of form since his £75m move from Everton last summer, had previously asked fans to "move on" from the chants on Friday, but that message failed to translate when the chant could still be heard from the stands.
A statement from Manchester United read: "The club and the player have been clear in asking for an end to the chant.
"The club is in discussion with the police and has asked for CCTV footage from Southampton."
United said they have a "zero-tolerance stance" on offensive chanting and behaviour, and look to take immediate action regarding the controversial matter.
Anti-discrimination group Kick It Out has described the lyrics, which regard the size of the 24-year-old's penis - as "offensive and discriminatory".
A spokesman for Kick it Out said: "Kick It Out would like to reiterate its stance that such behaviour has no place in football.
"Romelu Lukaku himself has requested that the supporters 'move on' from singing the chant in question and Manchester United now has a responsibility to ensure that the request is complied with."
Lukaku scored the only goal in United's tight victory over Southampton, which ensured they kept pace with their local rivals Manchester City. The Belgian has now scored six goals in as many games, and is currently level with Sergio Aguero and Alvaro Morata in the chase for the golden boot.