A 14-year-old boy has admitted a charge in connection with a series of stun gun attacks on female drivers in Birmingham.
Three women were attacked between 6 and 10 February in Moseley and Kings Heath, West Midlands Police said.
The teenager, from Sparkhill, appeared at Birmingham Youth Court to admit conspiracy to commit robbery.
He has been remanded in custody and is due to be sentenced at Birmingham Crown Court on 27 February.
The conspiracy charge also includes an incident on 10 February when two boys were stunned with a device during a robbery in which a mobile phone was stolen.
Earlier, police said two more teenagers have been arrested in connection with the attacks.
Both aged 16, the boys were arrested at their home addresses in Moseley and Balsall Heath on suspicion of conspiracy to rob.
A suitcase containing several sets of machetes, knives, hammers and mobile phones was found at one address, police said.