REXBURG (AP) — Police in Idaho say they’ve made no progress despite receiving hundreds of tips about two missing children whose parents aren’t cooperating with authorities.

The Rexburg Police Department has eight officers who are following leads that have come in from across the country in their search to find Joshua Vallow, 7, and Tylee Ryan, 17, according to the East Idaho News.

The children haven’t been seen since September.

Rexburg police say the parents, Chad and Lori Daybell, are named as persons of interest because they never reported the kids missing, have repeatedly lied about where their children are — initially saying the boy with special needs was in Arizona — and aren’t cooperating with the investigation.

“We just strongly feel that if the mom and dad felt like or if they knew that the kids were safe, they would show proof of it, but we have yet to see anything,” said Rexburg police Capt. Gary Hagen.

The couple issued a statement through an attorney last week, saying they love their son and daughter and look forward to addressing “allegations once they have moved beyond speculation and rumor.”

The couple married in recent months after both of their spouses died under unusual circumstances earlier this year.

Chad Daybell’s first wife, Tammy Daybell, was found dead at home in October. Initially thought to be a natural death, Tammy Daybell’s remains have since been exhumed in Utah, where she was buried. Autopsy results are pending.

Lori Daybell’s former spouse, Charles Vallow, was killed in July in Arizona in a confrontation with her brother, Alex Cox. Cox, who died on Dec. 12, said he shot Vallow in self-defense.

The FBI’s Salt Lake City office, the Fremont County Sheriff’s office and police in the Arizona cities of Chandler and Gilbert are also assisting in the case.