In what's thought to be the first conviction of its kind, a Canadian court recently found two parents guilty of taking their 13-year-old daughter across the border for a sexual purpose when she was forced to marry Warren Jeffs, as their Canadian sect leader alone has 145 children with 27 wives.

British Colombia Supreme Court Justice Paul Pearlman ruled Friday that former husband and wife Brandon J. Blackmore and Emily Ruth Gail Blackmore are guilty of taking their daughter across the border in 2004 to marry the now imprisoned Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS) leader Warren Jeffs.

FLDS Bishop James Oler was also on trial with the former couple, but Pearlman found him not guilty of the same charge.

Oler was accused of bringing the 15-year-old girl across the border to marry James Leroy Johnson, who was 24 at the time of the marriage.

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Brandon J. Blackmore was found guilty on Friday of taking his daughter across the border in 2004 to marry the now imprisoned Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS) leader Warren Jeffs. Above he arrives at the courthouse in Cranbrook, British Columbia

His estranged wife, Emily Ruth Gail Blackmore, was also found guilty of the same charge. She is pictured above on Friday arriving to court with FLDS bishop James Oler

Oler was also on trial with the former couple, but he was found not guilty. He was accused of bringing the 15-year-old girl across the border to marry James Leroy Johnson, who was 24 at the time of the marriage.

Despite the snowy weather,supporters of Brandon J. Blackmore, Gail Blackmore and James Oler attended the trial in Cranbrook on Friday

Pearlman said he couldn't prove that the man crossed the border with a 15-year-old girl who was later married to a member of the polygamous church. The Blackmores will be sentenced April 13 and face up to five years in prison.

The three defendants were members of the FLDS, a polygamous offshoot church that has members in the community of Bountiful in southeastern British Colombia.

Much of the evidence heard in the judge-only trial of the three defendants arose from a U.S. investigation into Jeffs, in which authorities say he married three underage girls - Millie Blackmore, Alyshia Rae Blackmore and Nolita Collen Blackmore - in 2004 and 2005 who were brought across the border to marry the now imprisoned leader.

Those same three girls are believed to be missing, as Canadian and United States authorities are both searching for them.

In addition, the charges against 59-year-old Winston Blackmore came after Special Prosecutor Peter Wilson approved three 'unlawful removal of a child from Canada…' charges against the former couple and Oler.

Winston Blackmore is married to 27 women with whom he has at least 145 children.

Millie Blackmore (above) was transported by her parents from Canada to the US to marry Warren Jeffs in 2004 when she was aged 13. Royal Canadian Mounted Police investigators are still searching for her

Alyshia Rae Blackmore (above) was also taken from the community in Bountiful to marry Jeffs when she was aged 12. Authorities are still searching for her as well

Millie Blackmore is not the only sibling of Brandon S. Blackmore who was married to Jeffs (above), as their sister Annie Mae Blackmore was married to the FLDS leader at an unknown date. Her whereabouts are unknown

Brandon J. Blackmore and Emily Blackmore are now separated as husband and wife, but the charges they were convicted of center on the couple's daughter, Millie Blackmore, who was married off to a then-48-year-old Jeffs in 2004.

Their son and Millie Blackmore's half-brother, Brandon S. Blackmore, testified against them during the trial, but he is hoping they receive leniency when they're sentenced.

In their defense, he said they were doing what they were told to by their prophet in terms of having his sibling marry Jeffs.

'I really do hope the judge takes into consideration the fact that my dad has already suffered a lot,' Brandon S. Blackmore told the Salt Lake Tribune.

'He has been cast out from the [FLDS] and his home and family.'

He shared that his father has 40 children and used to have five wives, but the FLDS excommunicated him when the investigation began.

Canada's biggest polygamist, Winston Blackmore (center), 59, is currently being prosecuted by the Canadian government for polygamy. He has 27 wives and 145 children

As the sect leader in Bountiful, British Columbia, Winston Blackmore had a large amount of children (above) and is accused of helping to arrange the cross border wedding ceremonies for child brides

Winston Blackmore is pictured above laughing with six of his 145 children, as some of the women hold their children which are his grandchildren in Canada

Winston Blackmore was charged again in 2014, and recently claimed that he and his wives are officially 'friends', adding that despite them being friends, 'they still charge us with polygamy'

The son added that his father now lives alone in a hamlet in southeast British Columbia. He said his father was hurt that the family members who were in the courtroom to hear the verdict wouldn't acknowledge him or look at him.

'I think that hurt him worse than the conviction,' Brandon S. Blackmore told the Salt Lake Tribune.

Last year, Brandon S. Blackmore revealed that his sibling was married to Jeffs moments before the leader presided over his wedding ceremony in Colorado City, Arizona, as he was a member of Jeff's flock at the time, according to VICE.

Millie Blackmore is not the only sibling of Brandon S. Blackmore who was married to Jeffs, as Annie Mae Blackmore was married to the FLDS leader at an unknown date.

Apparently Jeffs sent word to their father in Canada that he also wanted to take on Millie Blackmore as a bride.

A March 1, 2004 journal entry dictated by Jeffs to one of his wives and was later confiscated by U.S. authorities in Texas apparently reveals what happened.

'I sat down with Brandon [J] Blackmore and his wife and his daughter, gave a training on the redemption of Zion in brief, in summary, and this girl was called on a mission, and they received it joyfully,' the entry reads.

Above students at the Bountiful Elementary-Secondary School play an afternoon game of basketball. The community has two independent schools within a few hundred yards of each other

Students at the Bountiful Elementary-Secondary School play an afternoon game of basketball

Students who attend the Bountiful Elementary-Secondary School play a game of parachute during an afternoon recess

'And there Mildred Marlene Blackmore, age 13, was sealed to Warren Steed Jeffs for time and all eternity.'

It also notes that her father witnessed the ceremony to Jeffs, as Brandon S. Blackmore had no idea she had got married the same day or even that she was in Colorado City at the time.

He explained to VICE that he didn't see Millie Blackmore for years around the Bountiful community, as people claimed that she was 'on a mission for the church.'

In 2013, investigators with the Royal Canadian Mounted Police (RCMP) asked Brandon S. Blackmore to listen to a recording of Jeffs having sex, as they wanted to know if the person on the tape was his teenage half-sister.

Even though her name was not said aloud on the tape, he said could tell that it was his half-sister's voice and told RCMP investigators.

'He was asking her how it felt and a bunch of weird things,' Brandon S. Blackmore told VICE in an interview.

Brandon S. Blackmore shared that RCMP investigators told him the tape with Jeffs and his half-sister was recorded sometime around 2004 or 2005 at a motel in New Mexico.

Rachel Jeffs, the 32-year-old daughter from the FLDS leaders' second marriage confirmed that a series of teenage girls, including Millie Blackmore, had arrived to their household.

Young girls are seen playing outside one of the two schools in the polygamist community of Bountiful

It's not often that people who are not within the community are allowed in to photograph FLDS members . Above young girls play outside of school in Bountiful

Male students at the Bountiful Elementary-Secondary School play an afternoon game of basketball

A young girl is seen running from one building to another at a school in the polygamist community of Bountiful

Rachel, who left the sect in 2015, told VICE that when she inquired about who the girls were, she was told they would be new wives for her father.

She explained that she never asked her father about why he married girls who were underage.

'If you do, then you lose your place in the church,' Rachel explained.

'I wasn't so worried about losing my place in the church. I just would never get to see my family again.'

She shared that she remembered the teenage Millie Blackmore crying a lot.

Rachel added that the situation worsened when Alyshia Rae Blackmore and Nolita Colleen Blackmore arrived in December 2005 at the Yearning for Zion ranch, which is a compound for the FLDS in Texas.

'I saw her struggle emotionally a lot,' Rachel said of Millie. 'She wasn't really stable.'

Mounties with the RCMP launched a search for Millie Blackmore along with two other Canadian women, Alyshia Rae Blackmore and Nolita Collen Blackmore last year.

The other two women were also married to Jeffs when they were aged 12, as authorities believe all three of the women are now in their early to mid 20s.

Officials say much of the evidence for the cases against Winston Blackmore (above) and the other three members stem from the investigation into Jeffs

It is believed that the three missing women are still loyal to Jeffs, as many women apart of the sect are taught to be loyal to their husbands.

It's thought that Millie Blackmore, Alyshia Rae Blackmore and Nolita Collen Blackmore are all living on one of the many FLDS compounds in the U.S., or are being housed at secret locations that are known as 'Houses of Hiding' among members who are waiting for Jeffs to be released from prison (even though he is serving a life sentence).

The charges and convictions against Brandon J. Blackmore and Emily Blackmore are thought to be the first time that any parents within the religion have faced in relation to the reported pipeline of child brides that operated for years between the FLDS sects in Bountiful and the headquarters in Colorado City, Arizona and Hildale, Utah, according to VICE.

Oler was accused of having taken his 15-year-old daughter across the Canadian border to the U.S. to marry then-24-year-old James Leroy.

Oler was also charged with polygamy along with his brother-in-law Winston Blackmore, who faced the same charge previously years ago.

In 2007, Winston Blackmore was first arrested for polygamy, but those charges were later dropped over concerns of how the special prosecutor was selected, the Salt Lake City Tribune reported.

Winston Blackmore was charged again in 2014, and recently claimed that he and his wives are officially 'friends', adding that despite them being friends, 'they still charge us with polygamy'.

All of the marriages within the FLDS have been reportedly stopped since Jeffs arrest, but it's unclear if members of the religion have continued to transport child brides across the border.

Authorities in both the US and Canada have been searching for signs of human trafficking and other crimes that could possibly be happening by members of the FLDS.