The suspicious death of a popular librarian at Central Elementary School in Sugar City and the ensuing disappearance of her husband’s new stepchildren has caused area law enforcement and the FBI to ask the public’s help in searching for the missing youth.

Tammy Daybell, 49, died Oct. 19 at her Fremont County home. At that time her death was believed to be from natural causes. Further investigation by the Fremont County Sheriff’s Office determined that her death may be suspicious, a joint news release from the Fremont County Sheriff’s Office and the Rexburg Police Department said.

“Investigators determined that within a couple weeks of Daybell’s death, her surviving husband, Chad Daybell, had married Rexburg resident, Lori Vallow, who is the mother of the missing children,” the release said.

Fremont County Sheriff Len Humphries said his officers are dedicated to resolving the investigation. Chad Daybell and Lori Vallow are considered persons of interest, according to authorities.

“We’re working very hard to find more information and to follow up everything that we can,” Humphries said.

Police report that siblings Joshua Vallow, 7, and Tylee Ryan, 17, have been missing since September. Officers grew concerned about Joshua after relatives reported they hadn’t seen him for several weeks. Joshua is Vallow’s adopted special needs son, the release said.

“The welfare check was being conducted as extended family outside Idaho had not been able to speak with Joshua since September and were concerned,” the release said.

Officers contacted Lori Vallow who told them that Joshua was living with a family friend in Arizona. That claim turned out to be false.

Concerns also were raised after police learned Ryan had not been seen since September as well. The children’s extended family members told investigators they hadn’t had contact with either child since September.

“Additionally, the children have not been reported missing to any law enforcement agency and attempts to obtain the cooperation of Lori Vallow and Chad Daybell in locating the children have been unsuccessful,” the release said.

On Nov. 27, in an attempt to locate Joshua, the Rexburg Police Department executed search warrants in Rexburg locations that Lori Vallow was known to have visited.

“As the search warrants were being executed, investigators determined that Lori Vallow and Chad Daybell had abruptly vacated their residence and left Rexburg. (Rexburg Police) then requested assistance from the FBI in locating Joshua,” the release said. “Further investigation has determined that Lori Vallow and Chad Daybell did not appear to have Joshua with them when they left Rexburg. Investigators also determined Joshua last attended school at Kennedy Elementary in Rexburg on Sept. 23.”

Police are asking the public’s help in finding the children and are asked to call the Rexburg Police at 208-359-3000 if they have any information. They may also call the National Center for Missing and Exploited Children at 1-800-THE-LOST.