Kingston police arrested an 18-year-old Toronto man who they say was trying to throw contraband over the wall at Collins Bay Institution.
Police say they received a call about someone trespassing on the penitentiary grounds around 9 p.m. Tuesday.
The suspect fled the scene and entered the swampy area behind Kingston Mazda, according to police.
Officers then placed roadblocks around the swamp and the K9 unit was also brought in to assist.
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The suspect was located in the swamp just before 10 p.m.
He has been charged with trespassing and attempted trafficking of an illegal substance.