Italy's Football Federation (FIGC) has launched an investigation into anti-Semitic chants sung by Lazio fans before their team's win at Napoli, a governing body source told AFP on Wednesday.
The FIGC said they had launched the probe into the chants sung by a group of around 100 supporters behind the away section at the Stadio Maradona on Friday "and not heard in the stands during the match" by on-site officials.
A video showing Lazio fans singing the song in the presence of stewards and police went viral on social media in the aftermath of a 1-0 win in Naples.
In it, they proudly call themselves racist and insult supporters of local rivals Roma by saying their fathers were deported to Nazi concentration camps.
On Tuesday the FIGC had announced they were investigating unspecified chants directed at Napoli striker Victor Osimhen.
The incident is the latest in a litany involving Lazio's hardcore fans, some of the most right wing in a country where fascist fan groups are a widespread phenomenon.
In January, authorities ordered the closure of the Curva Nord section of the Stadio Olimpico, where Lazio's hardcore fans stand, for one match following racist chants at Lecce which left France international Samuel Umtiti in tears.
Last season the handler of Lazio's eagle mascot praised dictators Benito Mussolini and Francisco Franco after being suspended by the club for performing a fascist salute at the end of a match.