Dozens of state troopers and sheriff's deputies surrounded the town square in this tiny ranching hamlet as a grand jury opened its investigation into a polygamist sect accused of forcing underage girls into marriage and motherhood.

The main square in Eldorado was cordoned off with yellow police tape and a sheriff's department worker snapped photos of anyone who attempted to talk to sect members who arrived at the courthouse Wednesday and may be grand jury witnesses.

One witness subpoenaed to testify is a 16-year-old girl who denies state claims that she was married off at 15 and had a child soon after. She has asked for a new lawyer, claiming her court-appointed lawyer is lying about her.

Grand jury proceedings are supposed to be secret, but news of the meeting and the girl's subpoena have been disclosed in other court proceedings related to one of the largest custody cases in U.S. history. The girl is a daughter of Warren Jeffs, considered a prophet by members of the Fundamentalist Church of Jesus Christ of Latter Day Saints.

The girl and her mother said in a brief interview with The Associated Press they were told law enforcement would be testifying in the morning and they should come back in the afternoon.

"I don't want to do it," said the girl, shuffling her feet under a dark blue pioneer dress.

She said she doesn't know what she'll be asked. Her mother added, "We just kind of wonder what it's all about."

The Associated Press does not generally identify alleged victims of sex abuse.

The girl's attorney, Natalie Malonis, won an extension of a restraining order against FLDS elder Willie Jessop at a hearing Tuesday. Malonis claims Jessop is influencing the girl to be uncooperative, an accusation he denies.

The girl's mother said at Tuesday's hearing that Malonis also was subpoenaed to appear before the grand jury.

The criminal case follows state child welfare officials' ill-fated April seizure of more than 400 children at the Yearning For Zion Ranch in Eldorado. The children were scattered across foster-care facilities around the state.

The state accused the sect of widespread sexual abuse of teen girls, but the Texas Supreme Court forced the state to return the children from foster care earlier this month. The high court said the state overreached in taking all the children from the ranch when only a handful of girls may have been abused.

It's not clear what, or whether, criminal indictments of FLDS members may result, but prosecutions of sexual abuse crimes are difficult to prosecute without the victims' cooperation.

Under Texas law, a girl younger than 17 cannot generally consent to sex with an adult. Bigamy, which is generally considered a crime of fraud, is also illegal in Texas, although FLDS plural marriages were not sanctioned by the state.

FLDS leaders have consistently denied there was any abuse at the ranch and vowed earlier this month not to sanction underage marriages.

The state has DNA material collected from most YFZ ranch residents to help them sort out family groups after the April 3 raid, and FLDS officials fear the evidence could be used against them in a criminal case.

Texas Child Protective Services said it would turn over the DNA test results to prosecutors if it were subpoenaed by a grand jury or ordered by a court to do so.

Even if they had DNA evidence of abuse, prosecutors would have jurisdictional problems. Without the cooperation of the sect's teen girls, prosecutors will be unable to determine where any alleged abuse occurred. The sect has homes in Texas, Arizona and Utah and elsewhere.

The FLDS is a breakaway sect of the mainstream Mormon church, which renounced polygamy more than a century ago. Historically, church members lived along the Arizona-Utah line, where authorities had not sought criminal charges in decades until allegations of underage marriages — and willing witnesses — surfaced several years ago.

Still, just a handful of criminal cases have been prosecuted in the sect, estimated to have 6,000 members. Jeffs was convicted in Utah of rape as an accomplice for his role in the marriage of a 14-year-old and her 19-year-old cousin. He is in jail and awaiting trial on Arizona charges related to marriages involving young girls.