A fourth person has been charged over a violent armed robbery where an employee was hit with hammers in Port Kennedy earlier this year.
On June 7 four people entered a store on Fielden Way and allegedly attacked a staff member with hammers.
The employee received head and shoulder injuries, and required hospital treatment.
Three males aged 19, 18 and 17 were charged with aggravated armed robbery.
The fourth person, a 17-year-old was tracked down by the Regional Investigation Unit yesterday after he returned to Perth from New Zealand.
Officers charged him with aggravated armed robbery.
He will appear in the Perth Children's Court today.