Prosecutors have opened an investigation into alleged racist chants by Lazio fans against AC Milan's Tiemoue Bakayoko last weekend, the Italian Football Federation (FIGC) said Friday.
They are examining video footage from Milan's 2-0 win over the Roman club at the San Siro on Sunday, after Bakayoko and his club said he had suffered abuse, it said in a statement.
"The federal prosecutors' office has opened an investigation against Lazio following the complaint filed by AC Milan," the FIGC said.
The Serie A club had asked the football federation to investigate after Bakayoko said Lazio fans hurled racist abuse at him and his teammate Franck Kessie.
"To some Lazio fans and their racist cries towards to me and my brother Franck Kessie. We are strong and proud of our skin colour," the midfielder said on Instagram.
"I have my all (sic) confidence in our club to identify them."
Racist abuse in Italian football stadiums has been a serious problem in recent seasons, and Lazio have one of the worst reputations in the country, with a connection to the extreme right among the club's hardcore supporters which stretches back to at least the 1970s.
However, they are far from the only culprits, with monkey chants being aimed at black players by supporters of different clubs on a number of occasions.