The Metropolitan Police is being investigated over "the level of force" used to detain a teenage girl in Newham who was hit with a baton and Tasered.
The Independent Office for Police Conduct (IOPC) became aware of the incident which happened on 8 May at about 19:20 on Roman Road.
IOPC's Sal Naseem said: "Having reviewed the complaint and viewed body worn video footage of the incident we decided that this matter requires an independent investigation.
"It is important for everyone involved that we understand the circumstances surrounding this incident."
The Met Police said it made the referral to the IOPC.