(CNN) -- Alice and Gerald Uden seemed the typical family to the outside observer. They raised two children in rural Missouri, kept to themselves and attended church regularly. Even their next-door neighbors had little clue of the deadly secrets investigators say they've kept buried.
But this week the Udens, both now in their 70s, have been charged in slayings in cold cases dating back more than 30 years.
The news shocked many.
"They were good people; we've known them for about 12 years now. They're the kind of neighbors you leaned over the fence and talked about your chickens with," Allen Bishop told CNN affiliate KSPR. "They were just the old neighbors next door."
Now the elderly couple have been charged with killing their ex-spouses in separate, chilling incidents.
Gerald Uden has also been charged with the murder of his ex-wife's two children, who were 10 and 12 when they died in 1980, authorities said.
Authorities in Christian County, Missouri, arrested the couple, who are now in jail awaiting extradition to Wyoming, where the alleged killings took place.
Husband's body found in a mine
Alice Uden is suspected of killing her ex-husband, Ronald Holtz, in late 1974 or early 1975, when he was 25 years old. She was arrested Thursday and charged with one count of first-degree murder.
Alice Uden allegedly told an unnamed witness years ago about shooting her husband in the back of his head while he slept, according to a court affidavit.
Alice Uden told the same witness, according to court documents, that she had hidden Holtz's body in a barrel before dumping it a mine.
Holtz's remains were found in an abandoned gold mine in Wyoming, after an excavation in August.
Alice Uden and Holtz , a U.S. Army veteran, were married in September 1974. Alice filed for divorce a few months later, in February 1975. The divorce was granted, according to the affidavit, because Holtz was never located and served with divorce papers.
His wife and two boys shot
Gerald Uden is suspected of killing his ex-wife, Virginia, and her two children, Reagan and Richard, in September 1980.
He was charged Friday with three counts of first-degree murder, according to the Wyoming Division of Criminal Investigation. Gerald Uden told authorities Friday he shot his ex-wife and her two children with a .22-caliber rifle that she had brought so they could all go bird hunting, according to an affidavit.
Gerald Uden allegedly told officials he had picked up the three victims and drove them to Freemont County. When they got out of the car, he said he shot them all and attempted to hide their bodies, authorities said.
Investigators have not yet said whether the remains of the three victims have ever been discovered.
Gerald Uden's arrest seemed to have come about, at least in part, due to the arrest of his wife, for whom investigators had the initial warrant.
"As a result of the investigation, more evidence was obtained in reference to that homicide and Gerald Uden was arrested and charged with the three other homicides that occurred around 1980 in Wyoming", the Wyoming Division of Criminal Investigation Cold Case Team said in a statement.
They met each other
Somehow these two met each other. They left Wyoming and settled in the rural area of Chadwick, Missouri. Neighbors say they raised two children, attended church regularly and lived a good life.
Some were having a hard time believing the accusations against the Udens.
"I was in disbelief. They are old people. They don't do things like that," Bishop to KSPR.
The crimes, which occurred approximately five years apart from one another, have no listed motive in court documents.
CNN's Jennifer Feldman contributed to this report