Lori Vallow and Chad Daybell, are at the centre of a bizarre and long-running criminal investigation. They have now been charged with murder.
Both face first-degree murder charges for the death of Vallow's children from two previous marriages - Joshua "JJ" Vallow, seven, and Tylee Ryan, 17.
The bodies of the children were found at Mr Daybell's home last year.
The case has gained widespread media attention because of the couple's links to "Doomsday" apocalyptic beliefs.
Chad Daybell is an author who has written several apocalyptic novels loosely based on Mormon religious teachings. The couple are thought to have met through their involvement in a movement that promoted preparing for the end of the world.
Mr Daybell has also been charged with the murder of his ex-wife, Tammy Daybell, who died suddenly just weeks before he married Vallow.
Both have been in custody since last year and were previously accused of concealing evidence but Tuesday marks the first murder charges against them.
The couple also face conspiracy and other charges, including theft and insurance fraud.