A video which allegedly shows Durham cricketer Ben Stokes throwing punches in a street fight emerged on the day he was selected for the Ashes squad.
The England vice-captain was arrested on suspicion of causing actual bodily harm and released without charge on Monday, but remains under investigation.
Coach Trevor Bayliss has described the circumstances which led to Stokes' arrest in Bristol early on Monday as ''very unprofessional''.
A man said by The Sun to be Stokes is seen to throw punches at two others, in a video published on the newspaper's website last night.
The alleged incident took place in the Clifton Triangle area of Bristol at 235am on Monday, after which a 27-year-old man was taken to hospital.
The England and Wales Cricket Board said last night: ''We have seen this footage for the first time tonight - when posted by The Sun.
''There is an ongoing police investigation, which will look at all available evidence, and we do have to respect that process.''
Stokes retains the England Test vice-captaincy, in the immediate term at least, despite his arrest and a broken finger on his right hand understood to have been suffered during the night out.
The 26-year-old is currently still set to fly out with the rest of Joe Root's squad when they depart for the Ashes on October 28
ECB director Andrew Strauss stressed that, although no disciplinary action has yet been taken, Stokes and several other members of the squad will be quizzed in ECB's own investigation.
Strauss, who had not seen The Sun's video, said: "All we can do is deal with what we know and what we are in control of.
"We have no idea how things will pan out, and it would be wrong for us to second-guess that in any way.
"There is a disciplinary protocol in place as part of (the players') condition of employment - we need to follow that.
"They may be subject to disciplinary proceedings, including Ben."
In the 61-second video clip, the man alleged to be Stokes is seen to hit out and grapple with another man on the ground before seeming to throw a punch and fall to the pavement himself.
As the altercation continues, the man reported by the newspaper to be Stokes then throws another punch in the middle of the street and the person struck falls to the ground.