Warren Jeffs, the jailed leader of a polygamist sect, has been taken to a Texas prison hospital for an unknown reason. Jeffs is currently serving a life sentence for sexually assaulting two young girls.

A Texas Department of Criminal Justice spokesman confirmed Monday that the 58-year-old was taken to a prison hospital in Galveston last Tuesday, reports Reuters. He was admitted with “a non life-threatening medical condition” and is currently in stable condition. No further details were released.

According to The Los Angeles Times, Jeffs was serving his life sentence at the Palestine state prison in isolation.

Jeffs was the leader of the Fundamentalist Church of Jesus Christ of Latter Day Saints, a sect of the Mormon Church that preaches that polygamy will get a person a favored place in heaven. Prosecutors claimed that he had over 70 “spiritual wives.” His ranch was raided in 2008 and evidence obtained at the time was used to convict him of assaulting two young girls.

He was convicted in 2011 and was also hospitalized after a hunger strike that year. He is allowed visitors, but they must be over the age of 17.