Several schools in Byford, south-east of Perth, were placed into lockdown after police received reports that a boy was carrying an edged weapon near a school.
Police were called to Abernathy Road at about 2.25pm on Monday. The street is home to Byford Secondary College and Salvado Catholic College.
Western Australia Police said several schools in the area subsequently enacted lockdown procedures as officers attended the scene.
One male was apprehended and is assisting with inquiries, police said. No injuries have been reported and no edged weapon has been found.
