The Bag Under the Seat

A 9mm handgun was stolen in a break-in at a New Brunswick home. Police were told it had been sold to the Accused, who was banned by court order from having firearms. About a week later, police stopped a truck the Accused often used; he was not in it. The driver was arrested and 9mm ammunition was found. The driver said he was going to meet the Accused on a rural road to ride four-wheelers. Through miscommunication among officers, a sergeant came to believe the Accused was target shooting there, and ordered his arrest without a warrant for possessing a stolen firearm. Soon after, the Accused drove out of the area with two passengers and was arrested. Police found the stolen handgun in a bag under the passenger seat, a loaded clip, and 119 rounds of ammunition. His DNA was on the grip, along with two unidentified people's, and gunshot residue was on his hands. A passenger testified that the gun was hers and he knew nothing about it. Was the arrest lawful, and was possession proven?