Police said all four people inside a vehicle were ejected when it rolled east of Highway 2 on Sunday on the Blood Tribe Reserve.
One person died at the scene while the others, including the driver, were taken to hospital.
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Emergency crews were called to a reported single-vehicle rollover on Nov. 25 at about 6:45 p.m. The Blood Tribe Police Service responded, along with Blood Tribe EMS and fire crews.
The rollover happened on the First Nation on Township Road 41, east of Highway 2.
“Alcohol was determined to be involved,” police said in a news release Tuesday.
An RCMP collision analyst was called in to help with the investigation.
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Anyone who witnessed the rollover is asked to contact Blood Tribe police at 403-737-3800.
Blood Tribe First Nation is located about 60 kilometres southwest of Lethbridge.