Violent armed robberies may be linked

Police believe three violent armed robberies in Perth's northern suburbs may be linked.

The first offence occurred when a man used a gun to hold up a Bakers Delight store in Merriwa on 22 February.

Three days later police believe the same man approached three teenagers who were walking along Marmion Avenue in Butler and threatened them with a machete.

They ran away but the man tracked them down, pointed a hand gun at them and stole their belongings.

In the third incident a man was attacked with a machete as he walked through the grounds of Merriwa Primary school about 10:00 pm last Friday night.