The police did not inform the media of the arrest until Saturday. It is therefore correct to say police announced it Saturday, but the arrest itself took place Friday. Some news outlets may have erred and reported the arrest as taking place Saturday.
Since you're online ABro, maybe you can check this timeline and make sure it's accurate:
May 6th-Monday evening: TB goes on test drive-goes missing
May 7th-Tuesday: DM notifies staff not to go to hangar- for anything
May 7th-Tuesday: HPS release statement- TB is officially missing
May 8th-Wednesday-AJ goes to work and notices truck that matches TB's. AJ talks with his wife about it that night.
May 9th-Thursday-TB's phone is found in Brantford
May 9th-Thursday-AJ takes picture of truck and VIN number- calls CrimeStoppers-gets confirmation-holds family meeting that night and SS storms out of meeting.
May 9th- Thursday- in CN statement to LE, she assisted DM in moving trailer & truck to DM's mothers house and assisted moving incinerator into a stand of trees after they dropped trailer/truck off.
May 10th- Friday- early morning hours, CN statement to LE that she was with DM when he dropped off a locked tool box to a friends house.
May 10th- AJ goes to work at hangar and truck is gone- along with a car trailer.
May 10th, Friday- LE announce that they have located TB's phone.
May 10th, Friday- LE announce they're searching for 2 suspects and 1 has "ambition" tattoo on wrist where watch would be worn.
May 10th- Friday-LE visit the hangar after visiting another truck seller. Surveillance team put on hangar.
May 10th- AJ fired by DM. AJ gives statement to LE
May 10th- DM arrested on Cawthra Road
May 11th- late morning, LE make announcement of DM's arrest.