The 64-year-old sister's body was discovered in the convent at St. Berard Church by a colleague when she failed to show up for Sunday Mass.
FBI and state police authorities believe she was murdered. However, an FBI spokesman declined to say how Sister Marguerite died.
Darrin Jones, the agent, told Catholic News Service that an automobile Sister Marguerite had been using was discovered Nov. 3. Details about its discovery were not made available. It had been missing since her body was found.
Navajo is located near Arizona, about 40 miles northwest of Gallup. It is in the Diocese of Gallup, which covers part of northern Arizona and northern New Mexico.
Sister Marguerite had ministered at the parish since 1999, handling religious education and pastoral ministry duties. She also ministered to residents of the Navajo Nation in western New Mexico and eastern Arizona.
She had been a member of the Sisters of the Blessed Sacrament, based in Bensalem, Pa., for more than 40 years. She entered the order in 1966 and professed final vows in 1974.
Prior to arriving at St. Berard Parish, she had ministered in Dorchester, Mass., Lawtell, La., and in Pena Blanca, Laguna and Santa Fe, which are all in New Mexico.
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