Lazio president Claudio Lotito denies fans were involved in the stabbing of three Germans this week.
The incidents follow the attack on Tottenham fans in a Rome bar before their group phase match earlier this season.
There were three stabbings in different incidents ahead of tonight's Europa League match between Lazio and Borussia Monchengladbach.
None of the injuries are life-threatening, as two were stabbed in the buttocks and one in the hip.
"I would like to put these incidents in context," Lazio President Lotito told Sky Sport Italia.
"I spoke to the police and was told two of them weren't actually stabbings, as the people barely noticed the contact.
"I would also urge the media not to label the protagonists of all these incidents as 'Lazio fans.' Rome is a metropolis and as such is inhabited also by bad people.
"For example, there is no suggestion so far that those behind these incidents were part of Lazio's organised fan groups.
"Nobody is trying to justify this behaviour, but I say this because I am in constant contact with the police and want to understand if these people really are linked with Lazio.
"In my view they should do a quick trial and send them to prison for some time, so they don't have the chance to do it again."