John Casias found his calling when he joined a Texas church group that came to preach the Gospel in the little Mexican town of El Cercado in the early 1980s.
He later wrote that he saved nine souls, but worried how the villagers would grow without a teacher. By the time he returned to Texas, he knew his future would be as a missionary. When he told his wife, Wanda, she asked only what they would take and when they would leave.
"We were called to Mexico," son John Casias said his mother told him. "These are our people."
The bodies of John and Wanda Casias came one last time Thursday to the church they began, the Primera Iglesia Bautista Fundamental Independiente, in the violence-plagued region of northern Mexico, where mourners paid homage to the couple who were discovered strangled in their home two days before.
Dozens came from the community in the hills about 95 miles (150 kilometers) south of the Texas border, where the couple had many friends and ministered to the poor.
The attorney general's office for Nuevo Leon state, where couple lived, said Thursday the investigation is continuing and there have been no arrests so far.
Benjamin Frandsen came from Liberty Baptist Church, the Casias' home church in Lewisville, Texas, to mourn his longtime friends, and said their bodies would be taken to Liberty Baptist.
He said he came to the village in the hills outside Monterrey five to six times a year and met his wife there. He said the Casiases officiated at his wedding.
"I could die here or in the U.S., no one knows. But the security in Mexico has gotten worse, that's a fact," Frandsen said.
Increasing battles among drug cartels have spilled across the region, and people in the town now usually stay indoors after 8 p.m.
But relatives of the Casias' said the type of crime, belongings missing and a safe dug out of a wall, led them to believe that it could have been committed by someone the couple knew, not drug traffickers.
"My dad, being so kind, let them in," John Casias said. "I don't think he saw it coming."
Shawn Casias said he discovered the body of his mother at about 4 p.m. Tuesday when he went to their home to pick up a trailer.
He said she was lying on the floor with an electrical cord around her neck and a gash from a blunt object on her head.
The couple's Chevrolet Suburban was also missing, and Casias said he initially thought his father had been kidnapped.
But about four or five hours later, he said, a forensic investigator informed him that the body of his father had been found in a storage room of a small building on the property. His father also had an electrical cord around his neck.
John and Wanda Casias were originally from Amarillo, Texas. John Casias was 76 and Wanda was 67.
The municipality of Santiago, where the Casiases arrived in 1983 and built their church, sits in the mountains alongside a reservoir and tourist officials have designated it as one of Mexico "magic villages" for is colonial architecture and artisans.
But fighting between the Zetas and Gulf drug cartels has brought a surge of violence and other crimes to the area around Monterrey, Mexico's third-largest city, and it has largely emptied Santiago of tourists.
The Casias' church is on the highway south of the center of Santiago and the small ranch where they were found up in the hills about 20 minutes off the highway.
"They collected clothes and shoes and provided services for the poor," said Santiago Mayor Bladimiro Montalvo Salas, who attended the memorial service. "This is very sad. It's also very sad because it's going to affect the image of Santiago."
The younger John Casias said he and his siblings plan to find a way to continue their parents' mission.
The Casias children said their parents knew the dangers but couldn't be scared away.
"It's getting kind of rough there," son John Casias said he told them during their visit to his home in San Diego over Christmas, offering to let them stay with him for awhile. They refused.
"They understood it. They knew it. Were they scared to death? No," he said. "My parents did not live in fear. It's not in their DNA."
They were extremely humble, said son John, but his father wasn't always that way. In the 1960s in Amarillo, where he had a used car lot, John Casias wouldn't balk at spending $200 for a pair of shoes. But now he walked in shoes with holes and looked for the least expensive items he could find, subsisting on the generosity of church congregations across the U.S.
"They built a great ministry," John Casias said. "The love they had for the Mexican people. I had this conversation with them a thousand times ... 'We're going to die here. This is where He led us.'"
"If they had to do it over again they wouldn't do it any different," he said. "If my parents were here right now ... they would say pray for those who murdered us."
Associated Press writer Christopher Sherman reported from McAllen, Texas.