Mounties say 44-year-old John Wayne Sanderson was taken into custody at James Smith First Nation on Wednesday.
Police said Sanderson was one of four people wanted in connection to the disappearance of Gallagher. The first suspect was arrested at the beginning of June and three remaining wanted men were identified.
Gallagher was last seen in September 2020. Police announced in January 2021 they were treating her disappearance as a homicide, but her remains have not been located.
Officers said Sanderson was charged with indignity to human remains, and also has unrelated warrants with the RCMP.
He makes his first appearance in Melfort Provincial Court Thursday.
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