Several family members of late polygamist leader Ervil LeBaron may soon be brought to Utah to testify before a federal grand jury that is investigating the Oct. 19 slaying of ex-LeBaron lieutenant Dan Jordan near Manti.

Eleven people were named as material witnesses Thursday in a sealed federal indictment signed by U.S. Magistrate Ronald Boyce. They have not been charged in the slaying but may be detained for questioning."We can't tell you the names of the suspects we're looking for," an FBI agent in Salt Lake City said Thursday, but he confirmed the indictments were related to the arrest of LeBaron family members on July 1 for unrelated auto theft charges in Arizona.

The FBI in Phoenix identified those arrested as Ervil's son Heber, 27; Ervil's stepson Doug Barlow, 28; Cynthia LeBaron, 18; Richard LeBaron, 16; and Teresa

LeBaron, age unavailable. An FBI agent said he was unsure exactly how Cynthia, Richard and Teresa are related but said they are family members.

All five gave Phoenix police assumed names when they were arrested for possession of a stolen vehicle - a truck from Texas that matches the general description of a pickup used in the slaying of Eddie Marston, an ex-LeBaron follower, in Irving, Texas, on June 27.

Irving Police Sgt. Richard Gilmette said his department was sending an investigator to Phoenix on Friday to take a closer look at the impounded truck and to question the LeBarons.

The FBI in Phoenix said it is still seeking for questioning other LeBaron family members still believed to possibly be in Arizona, including two daughters of Ervil, Patricia and Natasha LeBaron.

Investigators said they also are seeking two other sons _ Andrew and Aaron LeBaron _ but they are not believed to be in Arizona.

An FBI agent in Phoenix said investigators from Utah, Texas, California and Arizona were trying to decide which agency may try to prosecute clan members first.

He said he assumed agencies from each of those states would soon have detainers or arrest warrants filed for crimes in their jurisdictions.

The five LeBaron family members were all initially arrested in Phoenix for investigation of auto theft. Heber and Barlow made bail but were re-arrested on charges of running a criminal enterprise for allegedly operating a multistate auto theft ring.

While the LeBarons were in jail, a Houston detective was calling areas that police believe have been frequented by the LeBarons. Phoenix police discovered they had arrested LeBarons when the Houston detective mentioned an alias a clan member had used. They were positively identified through fingerprints.

Police have said for weeks that Heber is wanted for questioning in the June 27 Texas slayings. Marston was killed in Irving and ex-LeBaron followers Mark and Duane Chynoweth, and Duane's 8-year-old daughter, Jennifer, were killed in Houston. A composite drawing of a suspect looks somewhat like Heber, investigators say. Heber also is wanted for fleeing prosecution in an armed robbery of a Richardson, Texas, savings and loan. Barlow is also being held on a Houston charge of auto burglary.

Police have said repeatedly that they want to talk to the LeBarons about the slaying of Jordan in Utah.

Just weeks before that murder, several of Ervil's children showed up at Jordan's home in Colorado and asked for his protection, saying they feared for their lives.

Jordan took them on a deer hunting trip to Utah where he was killed. Several were questioned at the crime scene but were not detained.

After Jordan's funeral in Colorado, one of Ervil's sons _ Aaron _ reportedly claimed life and death authority over Jordan's family and brandished firearms. Police arrested him for "menacing" but dropped the charges later when Jordan's family said it didn't believe it was in imminent danger from him.

After the arms-brandishing incident, other LeBaron family members who had been staying with Jordan's family were placed in foster homes. They all escaped from the foster homes on the same night.

An estranged wife of Andrew LeBaron told investigators in Texas that Andrew, Heber and Aaron held meetings in Colonia LeBaron, Mexico, where they talked of ways to control their younger brothers and sisters because "they are the future of the group."

Investigators suspect the LeBaron children may be carrying out a hit list of people who left their father's Church of the Lamb of God _ which has been blamed for more than 20 murders and disappearances.