Four members of a polygamist sect accused of being involved in a major truck theft ring in the Phoenix area have been indicted by a Maricopa County grand jury, the county attorney's office said Friday.

Named in the indictment are Douglas Barlow, 28; Richard LeBaron, 18; Tarsa LeBaron, 22; and Cynthia LeBaron, who gave authorities various birth dates, office spokeswoman Sylvia Lopez said.She said each of the four was being held under $274,000 bond pending their arraignments, which were set for July 29.

Each is charged with one count of conspiracy to control an illegal enterprise, one count of controlling an illegal enterprise and 20 counts of felony theft, Lopez said.

"The defendants are alleged to have conspired in the theft of 1986 and '87 Ford and Chevrolet pickup trucks," the spokeswoman said.

She said she could not elaborate on the charges because the indictment returned Tuesday remained sealed Friday "because there are other defendants."

Heber LeBaron, 27, was arrested with the others on July 1, but was not among those identified Friday as having been named in the indictment, Lopez said.

He is the son of the late Ervil LeBaron, founder of the Church of the Lamb of God. The sect has been linked to 18 deaths and disappearances over the past 22 years, including the October 1987 slaying of former sect member Dan Jordan of Bennett, Colo., at a deer-hunting camp in central Utah and the execution-style slayings last month of three men and an 8-year-old girl in Houston and Irving, Texas.

Texas authorities are attempting to extradite Heber LeBaron and Barlow, who are half-brothers. LeBaron is wanted on a November 1986 aggravated-robbery charge in Richardson, Texas, and Barlow is wanted in a vehicle burglary in Houston.

Police in suburban Mesa said earlier this week that the five sect members arrested in Phoenix may have been involved in a major theft ring that has stolen dozens of pickup trucks and four-wheel-drive vehicles.