Violent crime plagues northern Mexico, fueled by drug gangs, car thieves and kidnappers. On January 26, gunmen killed 58-year-old Christian missionary Nancy Davis as she and her husband Sam, both U.S. citizens, tried to run a roadblock on a lonely Mexican highway around 100 kilometers south of the Texas border.

At his home in south Texas, Christian missionary Sam Davis is left with only memories of his wife Nancy. ?She was a registered nurse and we built several clinics down in Mexico and she was a very giving person. She was always helping someone,? Davis said.

But violent drug gangs dominate life in northern Mexico, where the Davises worked.

Knowing that kidnap victims are often tortured, the couple had vowed not to be taken alive.

So Davis rammed his truck into the first vehicle in his path when armed men tried to stop them.

?I straightened my truck out so I would hit it with the side of my truck and it was just enough so I was able to get past this other truck that was sitting sideways and I got through there and, as soon as I did, the van that was behind me, those guys opened fire with their rifles on me and that is when a bullet came through the back window, through the headrest and into the head of my wife,? Davis said.

Davis braced for more bullets and kept going. ?I just stiffened my side and gripped the steering wheel expecting bullets to come into my side right there, but they were not counting on the high rate of speed I was going at and the bullets struck the truck behind the door and did not hit me and I got through,? he said.

Mexican federal police patrol the area, and Davis came across one.

?I slammed on the brakes, stopped and they said, 'Are they still coming?' and I said, 'Yes.' And they said, 'Then go, go as hard as you can and try to get away! We'll cover your back and try to hold them off.' And so I floored it [accelerated] and went on,? he said.

Davis made it to this border crossing at Pharr, Texas, and got his wife to a hospital. ?She was still breathing when we got there, but within 15 or 20 minutes she passed away and [sighs] has left a great big void in my life,? Davis said.

Davis remains committed to his projects in Mexico, despite the loss of his wife.

He says he loves the Mexican people. ?I have no anger. I love the people, all of them, even the ones who have done this. I pray for them,? he said.

Davis says crime in Mexico comes from poverty, and many people involved in drug trafficking there seek his help. ?They weep and cry and say, 'We wish we could get out of this mess, but, if we do, it will be our life, they will kill us if we try to leave or get out,'? he said.

Nancy Davis is buried close to where she and Sam lived in Texas just north of the border. He says he is determined to carry on the work they started together.