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Jacqueline Tarsa LeBaron was seemingly raised for vengeance.

The daughter of a third-generation polygamist sect leader, Jacqueline grew up as one of 54 siblings on a Mexican compound run by her father, Ervil LeBaron.

The elder LeBaron had a reputation for showing no mercy to those who disobeyed laws at his Church of the Lamb of God, and he passed those violent lessons on to his daughter.

In 1972, he was imprisoned in Utah on charges he ordered family members to kill his brother for going against his wishes. Those rival polygamists who refused to join his fundamental sect were also tagged by Ervil for execution.

Years later, investigators say, Jacqueline put those lessons to the test. She and her brother Aaron took control of the church following Ervil's death in prison. Ervil left behind an alleged "hit list" of sinners that Jacqueline took to heart.

In 1988, investigators say Jacqueline believed she got a message from God that the time was right to strike.

Jacqueline and Aaron raised money for the Church of the Lamb of God by stealing cars in the United States and selling them in Mexico, prosecutors said. When one of those stolen cars was found to have weapons, Jacqueline took it as divine providence that God was giving her the means for revenge.

"Jacqueline — who was, if you’ve seen 'The Godfather,' would be like the consigliore to Aaron at that time — said 'This is a sign of God. We’ve got to go kill the sons and daughters of perdition,' which is what you were named if you left the Church," said Terry Clark, the assistant U.S. Attorney in Houston.

Jacqueline and Aaron plotted and ordered the deaths of three sect members who had fled the group and started new lives in Texas, prosecutors said.

"They ascribed to a thing called blood atonement, which basically meant for you to go to heaven you had to be killed," Clark said. Their teachings were based on a book Ervil wrote while in prison.

In June 1988, members of the church simultaneously gunned down brothers Mark and Duane Chynoweth and Ed Marston in Houston and Irving, Texas.

"Part of the instruction was to kill anybody over 6 years old who saw what happened," Clark said.

So the members also shot Duane's 8-year-old daughter, Jenny, in the head, murdering the only witness to their crime.

"This is about the best planned murders I’ve ever seen in 30 years of prosecution," Clark said. "It put the Mafia to shame."

Three members of the LeBaron family were found guilty of the murders, a fourth pleaded guilty and a fifth was convicted of ordering the assassinations.

An Oct. 14, 1992, authorities charged Jacqueline LeBaron with conspiracy to commit murder for consideration, murder for consideration, conspiracy to tamper with a witness, tampering with a witness, use of a firearm during a crime of violence, conspiracy to obstruct religious beliefs, obstruction of religious beliefs, RICO conspiracy and RICO.

But for 20 years she has eluded authorities.

Raised on the Baja Peninsula, Jacqueline LeBaron is a Mexican national and "can speak Spanish like a Mexican and not like an American, so it’s very easy to blend in and just disappear pretty much anywhere in Central America," Clark said.

Now 42, Jacqueline is 5-foot-11 with brown hair and green eyes and weighs about 135 pounds.

Authorities believe she may be teaching English to wealthy Mexican families. She's been known to use the aliases Melanie Martin, Tarsa LeBaron, Melanie Anne Martin, Jacqueline LeBaron, Jacquelyn Tarsa LeBaron, Jacquelyn LeBaron, Amanda Susan Emerson, Karen Howell, Tarsa McDonald, Malanie Anna Martin, Melonie Martin, Mitzi Diane Mathison, Elizabeth Shelton, Jacqueline Hawkins-Varela and Hawkins-Varela.

She's also been known to wear disguises and may possess a firearm.

Clark described her as "very articulate, very bright."

"If you would ever meet any of these folks to talk to them you wouldn’t even suspect that they were engaged in the conduct that they engage in," Clark said.

The FBI is offering a $20,000 reward for information leading to Jacqueline LeBaron's arrest and conviction. Anyone with information is asked to call the FBI at 202-324-3000.

Click here for more coverage and to see LeBaron's FBI poster profile.