Things began changing in the 1980s, when small groups started crossing his property, becoming more brazen every year. They cut the fence instead of climbing over. Drug-laden vehicles began motoring through the sagebrush. Once, Mexican army soldiers came across and disarmed him after he reported suspicious drug activity at a Mexican ranch nearby, Maupin said.
By the late 1990s, immigrants were streaming across every night, Maupin said. He brought in friends to help him patrol, including a former Marine sniper who gave him shooting lessons. They'd confront and hold groups regularly until agents picked them up.
One cold night, a lost group knocked on his door. Maupin and his wife, Jeanette, 69, gave them hot chocolate and let them warm up by the fireplace. "There were two little girls with them, in cotton dresses and sandals, shivering," she said.
Maupin estimates that over the years, he and his friends rounded up thousands of illegal border crossers.
He strengthened the original 100-year-old fence with rebar and barbed wire, but nothing much worked until border authorities last year plugged gaps in the government's original fence and added the 18-foot-high barrier east of his property.
After Rosas was slain last July, the agency beefed up even more. Agents now man an outpost on a rock mountain overlooking Maupin's property and drive by regularly along the border road.
It's been about eight months since he has had to repair his fence, a record, he said. Still, with organized crime groups battling south of the border, he believes threats remain. He points to the towering barrier nearby.
"When they put another one like that, over here — a double fence," Maupin said. "Then I'll have to stop calling it the department of homeland insecurity."