The police watchdog is to probe the release of footage to the media of a disturbance at Manchester Airport.
A mobile phone video clip of a police officer kicking Fahir Amaaz in the head went viral on social media as he and his brother were restrained.
Further footage, obtained by the Manchester Evening News, emerged days later which showed the immediate lead-up to the incident on 23 July.
The Independent Office for Police Conduct (IOPC) said it would investigate whether the film "was provided by someone working for Greater Manchester Police and, if so, the justification for this."
The footage showed two police officers being hit to the ground before Mr Amaaz,19, was incapacitated with a Taser.
Last month, both brothers from Rochdale appeared alongside their solicitor Aamer Anwar at a press conference in Manchester city centre to "set the record straight" after what they called "a deliberate attempt to smear the family".
Mr Anwar told reporters of the family's unhappiness at the release of the new footage and queried how it had come into the public domain.
A spokesman for the IOPC said: "Following a press conference on August 6 2024, when concerns were raised about the source of a video provided to the media, we received a conduct referral from Greater Manchester Police (GMP).
"This referral, whilst considering other possibilities, relates to whether someone employed by the force may have shared footage relating to an active police investigation without a legitimate policing purpose.
"We are in the early stages of an independent investigation, which will consider whether there is any evidence to suggest this was provided by someone working for GMP and, if so, the justification for this."
The IOPC is also probing the actions of the officers involved in the airport disturbance.
One officer is under criminal investigation for assault in connection with the arrests of the brothers.
He has also been suspended by GMP.
A second officer has been advised they are also under criminal investigation for assault over an incident shortly after two other men were arrested.
In a separate probe, GMP has passed a "comprehensive" file of evidence to the Crown Prosecution Service as part of its investigation into the incident which saw three of its officers injured.
Four men, including the two brothers, arrested on suspicion of affray and assault remain on bail.