BOISE, Idaho (AP) — Investigators returned Tuesday to search the Idaho home of a man with ties to the mysterious disappearance of two children who haven't been seen since last year. It's the second search of Chad Daybell's home in a case that has vexed investigators for months and attracted worldwide attention.

Seven-year-old Joshua “JJ” Vallow and Ryan, 17, haven’t been seen since September, and police say both Chad and Lori Daybell lied to investigators about the childrens’ whereabouts. Besides the missing children, the couple has been under scrutiny following the deaths of both of their ex-spouses, as well as Lori Daybell's brother — the shooter of Lori Daybell's ex-husband.

The Rexburg Police Department announced Tuesday morning that officers were searching Chad Daybell's eastern Idaho home, along with investigators from the FBI and the Fremont County Sheriff's Office. The search warrant is sealed, Rexburg Assistant Police Chief Gary Hagan said in a statement that he couldn't reveal details other than to say the search was linked to the disappearance of the children.

Lori Daybell is currently awaiting trial on charges of child abandonment and obstructing the investigation, and the Idaho attorney general's office announced earlier this year that it was investigating Chad Daybell in the death of his then-wife, Tammy Daybell.

The complicated case began last summer, when Lori Daybell's former husband Charles Vallow was shot to death by her brother, Alex Cox, at Vallow's Phoenix, Arizona, home. At the time, Cox said the shooting was in self defense. Charles and Lori Vallow had been estranged, and in divorce documents Charles Vallow claimed Lori believed she had become a god-like figure who was responsible for ushering in the biblical end times. Cox died in December of an apparent blood clot in his lung.

Shortly after Charles Vallow's death, Lori and her children moved to eastern Idaho. Tylee Ryan was last seen in September headed into Yellowstone National Park with her mom and other family members for a day trip, and JJ was last seen by school officials several days later.

Police began investigating the children's whereabouts after extended family members raised concerns. Investigators have said both Chad and Lori Daybell lied to investigators, claiming the children were staying with friends.

Tammy Daybell, died in her sleep last October of what her obituary said were natural causes. Fremont County authorities grew suspicious when Chad married Lori Daybell just two weeks later, and they had Tammy Daybell's body exhumed in December. The results of that autopsy have not been released.

Lori Daybell has pleaded not guilty to the charges against her and Chad Daybell has not been charged in connection with the case. Law enforcement officers first searched Chad Daybell's home on Jan. 3, removing more than 40 items including several pieces of computer equipment.