Manchester City midfielder Yaya Toure has described the racial abuse he has been subjected to on social media as a "disgrace."
Police are investigating after Toure, 31, was sent racist messages within hours of reactivating his Twitter account on Monday.
The Ivory Coast international posted his first message in five months after City's 1-0 win over Manchester United on Sunday, having previously withdrawn from the social network site to concentrate on the World Cup.
Toure told BBC Sport: "For me it's a disgrace to be honest. We need to do something to try to tell people those kinds of behaviour have to stop. I want those people to understand what they're doing is wrong.''
The offensive responses to Toure's post prompted anti-discriminatory body Kick It Out to make an official complaint to the police on Monday.
Greater Manchester Police confirmed on Tuesday that complaint had been received. The force has yet to issue a formal statement but a tweet in response to a query about the matter confirmed it was under investigation.
It read: "Thank you -- we are aware if [sic] this and are investigating.''
The incident comes just over a year after Toure was the subject of racist chants from supporters during a Champions League group game at CSKA Moscow.
The midfielder was upset by that abuse and even suggested black players could boycott the 2018 World Cup in Russia if the issue was not tackled in that country.
UEFA punished CSKA, ordering them to play their next home game in the competition in a partially closed stadium.
Two further offences led to the Khimki Arena being closed to paying spectators when City visited again in this season's Champions League. CSKA will also have no fans present when they play City in the return fixture at the Etihad Stadium on Wednesday.
City manager Manuel Pellegrini, meanwhile, said on Tuesday that he is confident the latest issue will not adversely affect Toure on the field.