England must explain the tunnel fracas involving star centre Owen Farrell at Murrayfield, following a request for clarification by Six Nations Rugby.
The Rugby Football Union and its Scottish counterparts have been asked to provide their accounts of the scuffle that took place shortly before Eddie Jones' men were defeated 25-13 in a pulsating Calcutta Cup match.
TV footage appears to show a clash between Farrell and Scotland No.8 Ryan Wilson that ended when they were pulled apart by team-mates.
The incident unfolded as the players left the pitch and entered the tunnel upon completion of their warm-ups.
"Six Nations Rugby will be writing to the unions to request clarification on what happened in the tunnel," a Six Nations spokesperson said.
Once the unions have responded, tournament organisers will decide whether to launch an investigation or initiate disciplinary proceedings.
Jones repeatedly denied knowledge of what had taken place, as did every player from both teams when asked for their version of events.
Scotland captain John Barclay said he was in the toilet at the time.
"I've been coaching a game. I've been pretty busy. Are you aware of it? You can show it to me after the press conference, then we can have a chat about it," Jones said at the post-match press conference.
"In all seriousness, I don't know about it. If there was, we shouldn't let that detract from a great Scotland victory. Don't get distracted by other things. Have you got an iPhone 10? The vision's better on an iPhone 10."
When asked about the scuffle and whether it was evidence that England had lost their heads, Jones replied: "Look I don't know, I don't think so. These things happen."