OTTAWA—When my childhood friend Gladys Simon disappeared in 2004, at the age of 41, the list of possible scenarios that ran through the minds of those who knew and loved her were endless. But for the police investigating her disappearance, there seemed to be only one possible explanation. Gladys was Mi’kmaq. She was a patient at the Restigouche Hospital Centre in Campbellton, N.B. And police simply assumed Gladys had walked away from the facility.