HAMILTON - Hamilton police have issued an Amber Alert for a missing teenager in Ontario.

Austin Large, 13, is believed to be in the company of his father Elias Large.

Austin is described as a white male, 5 foot 5 inches, 160 pounds, with a heavy build, brush cut, light brown hair and blue eyes.

Det.-Sgt. Chris Kiriakopoulos said Monday night that the boy, from Ancaster, Ont., is autistic and does not have his medication.

The boy and his father were to have left for a fishing trip on Friday but Austin was not returned to his mother on Monday as planned.

Kiriakopoulos said they grew suspicious after they found that the two did not go to Lake Nipissing as suggested and that it was rare for the boy to go with his father.

The father and mother are estranged.

The father and son are thought to be in a 1999 GMC Sierra truck-extended, with a white, large green tool box with Ontario licence plate number NE7 917.

People who have seen the two are asked to call 911.