After their 2-1 quarter final first-leg defeat, on the ground where Roma suffered an humiliating 6-1 loss in the group stages back in October, the Italian side's captain Lorenzo Pellegrini said goalkeeping coach Nuno Santos had been attacked.
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In a statement released on Friday, the Norwegian team insisted it was Roma who were the aggressors.
"A proven violation of the rules of the game is that the goalkeeping coach of Roma positioned himself illegally outside the coaching staff, where he continuously verbally and gesturingly harassed Knutsen," the statement read.
"Glimt made the fourth referee and UEFA's delegate aware of this on several occasions. The complaints were not heeded and Roma's goalkeeping coach was allowed to continue his behaviour unhindered."
Knutsen added in the statement: "Everything culminated in a physical attack on me in the tunnel. Usually I'm so calm by nature that I would withdraw. In this case, I was physically attacked. He (Santos) grabbed me by the throat and pushed me into the wall. It is only natural that I then had to defend myself."
Pellegrini had a different version of events on Thursday.
"Even their coach attacked our goalkeeper coach Nuno Santos," he told Sky Sport Italia. "I think this is an insult to the competition. I think it is an insult also to Rome and to the Romans.
"I am honestly still shaken by what I just saw, it's absolutely shameful. Now we want to send Bodo home, also because of what happened off the field."
European soccer's governing body UEFA said it was looking into the matter.
"A UEFA Ethics and Disciplinary Inspector has been appointed to conduct a disciplinary investigation regarding reported incidents which allegedly occurred," a statement read.
Bodo highlighted one particular piece of evidence they want made public.
"Roma is bombarding the media with untruths, in an attempt to hide the unsportsmanlike behaviour," they added. "Glimt knows that there is a video of the incident, which shows the attack on Knutsen from representatives of Roma's support staff.
"The club has seen this video. We demand that the public have access to this video owned by UEFA."
Bodo added they plan to report the incident to the police, but the local authorities said they were yet to receive anything.
Roma coach Jose Mourinho was also unhappy with the artificial pitch in Norway, blaming the synthetic surface for defender Gianluca Mancini's injury that forced him to be substituted on Thursday.
"It's a pity that we had an important injury, which I call the injuries of the plastic pitches," Mourinho told BT Sport.
"It's out of our control. People decided that European competitions can be played on plastic pitches, so we have to play."
The teams meet again next week in the second leg in the Italian capital.