Editor's note: Salt Lake Tribune reporter Nate Carlisle, on assignment for the news outlet VICE, recently traveled to British Columbia to report on Canada's investigation into the Fundamentalist Church of Jesus Christ of Latter-Day Saints. Read the full story at VICE.com. The following is a digest version.

Brandon S. Blackmore listened carefully. He had to hear past the hissing sound in the recording, and the panting.

One voice on the recording was unmistakable — the soft, monotone tenor of Warren Jeffs, North America's most infamous polygamist and the president of the Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS).

Brandon (there are so many people in the polygamous sect with the same last names, you're better off calling them by their first names) once had been a member of the church, which believes practicing polygamy helps one achieve eternal salvation. And he had been obedient to Jeffs, the church's president, who followers believe is a prophet who speaks to God.

Warren had even officiated at his wedding in 2004. And, as it turned out, just a few minutes before that ceremony, Warren, who was 48 at the time, had married Brandon's 13-year-old half-sister, Millie, as one of his plural wives.

Now it was August 2013. Two investigators from the Royal Canadian Mounted Police had asked Brandon to listen to a recording of Warren having sex. They wanted to know whether he heard Millie's voice. Yes, Brandon said, it was Millie on the tape. Although her name was never said aloud, he could tell by the voice that the woman Warren was having sex with was his half-sister.

"He was asking her how it felt and a bunch of weird things," Brandon said in a recent interview with VICE. He declined to elaborate on what else he heard in the tape — the existence of which has not previously been publicized — but he said investigators told him it was made in 2004, at a motel in New Mexico.

The RCMP wanted confirmation of Millie's voice as part of a case they were building against Millie's parents, Brandon J. Blackmore and Emily Gail Crossfield, who had taken their preteen daughter to Colorado City, Ariz., to marry Warren.

In 2014, the year after the Mounties asked family members to listen to that recording, Blackmore and Crossfield were charged with one count each of removing a child from Canada for the purposes of sex.

At the same time those charges were filed, prosecutors charged two former FLDS bishops from British Columbia, Winston Blackmore and Jim Oler, with polygamy.

The cases against the four remain active. So, too, is the RCMP investigation.

The prosecutions are believed to represent the first time parents have been held criminally responsible for the FLDS' 1,100-mile child-bride pipeline that has for decades run back and forth from Bountiful, in British Columbia, to the twin towns of Colorado City and Hildale, Utah, collectively known as Short Creek.

The Stop Polygamy in Canada Society, an Alberta-based organization that has urged tougher stances toward polygamists, published a list of 41 Canadian girls who were married in the United States to FLDS men. The marriages occurred from 1990 to 2006 with brides ages 12 to 17.

Interviews reveal that Canadian law enforcement officers have continued to question FLDS defectors in the United States and Canada in an attempt to learn more about how the sect's bride pipeline worked and whether there is evidence to charge anyone else with a crime. As recently as last fall, investigators with the RCMP traveled to the U.S. to speak with two of Warren's daughters and two of his former confidants, among others.

The Mounties also are trying to find Millie and two other Canadian women, Alyshia Rae Blackmore and Nolita Colleen Blackmore. Both were married to Warren at age 12. The three brides, all who would now be in their early to mid-20s, are thought to still be loyal to Jeffs, and are likely to be living on one of the sect's compounds in the American West, or at secret locations known among FLDS members as "Houses of Hiding."

RCMP Sgt. Terry Jacklin, a Mountie in southeastern British Columbia who has been on the trail of the FLDS for years, confirmed in an interview with VICE that the investigation is ongoing, and that more criminal charges are possible. Although Jacklin would not go into detail about the investigation, he said that the RCMP is working with law enforcement in the U.S., and that he and his partner may travel to Utah again "within the next couple of months."

Jacklin said the RCMP is working with U.S. agencies, though he declined to specify which ones.

"We are still building, we are still gathering evidence," he said, "and we are still in the process of providing more information to our prosecutor in respect to additional charges against additional people." ...

... Jacklin also acknowledged a potential obstacle to the investigation — one that additional manpower or overtime hours won't be able to solve. "Some of these girls don't see themselves as victims," he said.

| Courtesy Rachel Jeffs Millie Blackmore.
| Courtesy Rachel Jeffs Millie Blackmore.

Editor Note:Brandon S. Blackmore listened carefully. He had to hear past the hissing sound in the recording, and the panting. One voice on the recording was unmistakable — the soft, monotone tenor of Warren Jeffs, North America’s most infamous polygamist and the president of the Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS).