SALT LAKE CITY -- A bigamy investigation has been launched into a polygamous family starring in a reality television show, police said Tuesday.

Lehi police Lt. Darren Paul has said the probe was triggered by the reality television show "Sister Wives," which features 41-year-old advertising salesman Kody Brown and his four wives, 13 children and three stepchildren. The TLC program premiered Sunday.

Brown is only legally married to Meri but also calls three other women his spouses: Janelle, Christine and Robyn. The three stepchildren are from Robyn's previous relationship.

Christine Brown declined to comment Tuesday, although the family issued a statement through TLC that it was disappointed.

"...When we decided to do this show, we knew there would be risks," the family said. "But for the sake of our family, and most importantly, our kids, we felt it was a risk worth taking."

The Browns have said they hoped that the reality show's peek into their lives would help broaden the public's understanding of plural families.

Across Utah and parts of the western U.S., polygamy is a legacy of the early Church of Jesus Christ of Latter-day Saints. Members brought the practice to Utah in 1847, but the Mormon church disavowed plural marriage in 1890 as part of a push for Utah's statehood.

The modern Mormon church excommunicates members found engaged in the practice, though an estimated 38,000 self-described fundamentalist Mormons continue to believe and/or practice polygamy, believing it brings exaltation in heaven.

Although it is rarely prosecuted, bigamy is a third-degree felony in Utah, punishable by a prison term of up to five years. Under the law, a person can be found guilty of bigamy through cohabitation, not just legal marriage contracts.

Lehi police said the evidence gathered from the probe will be turned over to the Utah County attorney's office for possible prosecution. A telephone message left for Paul was not immediately returned Tuesday.

Utah last prosecuted a polygamist for bigamy in 2001. Tom Green, who was married to five women and drew the attention of Utah authorities after promoting his lifestyle on national TV talk shows, was convicted on bigamy, criminal nonsupport and child rape charges. He spent six years in prison and was released in 2007.

Most polygamists do not belong to organized churches, although a polygamy advocacy group has identified 11 distinct communities ranging in size from about 150 to 10,000.

The Utah attorney general's office has investigated the state's secretive polygamous communities, but focused its efforts on cases involving allegations of abuse, sexual assault and fraud, not bigamy.

"It has been our office's position not to pursue cases of bigamy between consenting adults," the attorney general's spokesman, Scott Troxel, said Tuesday. "We want to use our resources wisely."

Over the past 10 years, Utah's historically insular polygamist community has worked to educate the public and state agencies about its culture. State agencies now better understand the unique aspects of polygamous culture and plural families are less hesitant to seek help when needed, Principle Voices co-founder Anne Wilde said.

The Brown family's decision to do a reality TV show was sort an extension of that education work, said Wilde, who knows the family well. Now she fears an investigation will cast a pall over any progress and instill fear in plural families.

"If it really goes to a court situation, then our people are going to go right back into isolation," she said.