An Idaho mother jailed in connection to the disappearance of her two children is being investigated for murder, attempted murder and conspiracy in the death of her husband's former wife, according to court documents.
Lori Vallow is under investigation along with her husband, Chad Daybell, in the death of his late wife, Tammy Daybell, NBC affiliate KTVB in Boise reported.
Tammy Daybell's body was found in her home in October, a death initially ruled as natural but since classified as suspicious. In December, the 49-year-old's remains were exhumed so an autopsy could be conducted, the results of which are still pending, according to KTVB.
Chad Daybell and Vallow married weeks after Tammy Daybell's death. They have not been charged in the case.
The state Attorney General's Office said in a letter that it is taking over the investigation and that "all decisions regarding the case shall be the responsibility of the AG," KTVB reported.
The letter says that the Fremont County Prosecutor's Office, which was initially handling the case, will still pay all necessary expenses.
Vallow is currently in jail in Idaho in connection to the disappearance of her children, Joshua Vallow, 7, and Tylee Ryan, 17.
The siblings were last seen in September, but an investigation into their disappearance didn't begin until November, after police in Rexburg, Idaho, tried to conduct a welfare check on Joshua.
In a December statement, police said Vallow and Daybell were refusing to cooperate with the investigation into the missing children and had left the state.
Police have said Vallow either knows the location of her children or knows what happened to them.
After Vallow and her husband were found in Hawaii, she was arrested in February and extradited to Idaho on charges of desertion and nonsupport of dependent children. She is being held on a $1 million bond.
According to The Associated Press, Vallow has pleaded not guilty to the charges. Chad Daybell, a self-published author who has written more than two dozen books about near-death and doomsday events, has not been charged in connection Joshua and Tylee's disappearance.