An American missionary has been killed in Mexico by what police suspect were drug thugs.

Nancy Davis and her husband Sam, both Christian missionaries, were aware of the escalating drug violence in Mexico and had been chased by gunmen on previous occasions.

But they kept going back, according to a report by ABC News.

Davis told friends when she last saw them over dinner this fall that she “might not come back alive” from her next visit to Mexico.

“Every day that passed they had personal friends, people in Mexico that they were acquainted with who were dying. It was all around them. They were constantly getting threats. Many, many times they had been chased and managed to elude danger,” Jennifer Christner, a friend of the couple, told ABC News.

Christner and her husband, the pastor of the Christian Chapel Church that Nancy Davis grew up in and the couple visited each year, said that the couple discussed the dangers of living in Mexico over dinner in November of last year, ABC News reported.

“They knew that when they left, we might not see them alive again,” Christner said. “They said, ‘We know when we go back in, we might not come back alive and if that’s the case, know that we died doing what we were supposed to do.’”

Nancy Davis told Christner, “If I don’t see you here, I’ll see you in heaven.”

According to the ABC News report, Pharr (Texas) Police Chief Ruben Villescas said Nancy and Sam Davis were riding along a highway 70 miles south of the border town of Reynosa, Mexico, on Wednesday when they approached an illegal roadblock. Rather than stop, they continued driving and were chased by several gunmen in a black pick-up truck.

ABC News reported that rather than stop, Sam Davis gunned the engine of their blue 2008 Chevrolet pick-up, a vehicle popular with the dangerous Zetas drug cartel that controls the area. The pursuing gunmen fired at Davis’ truck, and a bullet hit Nancy Davis in the head.

Sam Davis raced the 70 miles to the Pharr International Bridge, speeding the last part of the way against on-coming traffic to avoid the long lines of northbound cars at the border checkpoint, arriving at 12:25 p.m., according to police reports.

Nancy Davis was rushed to a hospital in the border city of McAllen, Texas, but she was declared dead at 1:54 p.m.

Christner said that the couple spent 90 percent of their time in Mexico.

“They lived, breathed, ate, slept Mexico,” Christner said. “That was their life…they would come out long enough to get mail and take care of any business that they needed to.”

ABC News said the couple raised two sons in Mexico.

Their son Joseph Davis told the Associated Press that the couple knew the risks of Mexico’s escalating violence and said “it would be easier” to count the number of times that they had not been targeted during trips to Mexico in recent years.

The couple’s family is in shock, Christner said, and she worries about how Sam Davis will handle his wife’s death.

“They came as a package together and I cannot imagine one living without the other. They’re very, very in love,” Christner said.

ABC News stated that Nancy Davis, an Ohio native, married Sam Davis at Christian Chapel Church in 1972. It was a church that her father helped found. The two left shortly after being married and became missionaries in Mexico.

The two loved to sing. Nancy Davis has released several songbooks, Christner said. A YouTube video shows the couple performing at Christian Chapel Church in October of last year for the 60th anniversary of the church’s founding.

Nancy Davis can be seen playing the accordion while her husband plays the guitar. As she sings, she lifts her arms in the air.

“Praise God, he’s marching on he…he can still guide the darkest night,” the couple sings in the video.