Mexican officials have nonetheless become frustrated by attention to this agricultural area’s slide into chaos, with drug cartels battling armed self-defense groups. And in Washington, influential lawmakers, including Robert Goodlatte, the Republican chairman of the House Judiciary Committee, are increasingly concerned that criminals are abusing the asylum process, cheating their way into the country and disappearing for at least a few years until their cases are heard.
Mr. Contreras’s efforts rouse both concerns. In the 2013 fiscal year, most of the petitions for asylum based on a “credible fear of persecution or torture” came from Central America. But of the roughly 2,500 cases that came from Mexico, Mr. Contreras estimated that nearly 80 percent of them involved his letters. Officials with the Department of Homeland Security said they considered that more or less accurate.
And each case is a riddle. Are Mr. Contreras’s assertions of the dangers here enough to give emigrating families a chance of asylum in the United States? Are the letters showing up at the San Diego border even originals?
Sometimes yes, sometimes no, immigration authorities say. The circumstances are often so murky that even members of the same family, carrying the same letter, say they have received different decisions on their requests to stay in the United States and apply for asylum.
“The letters are a product of need,” said the Rev. Manuel Amezcoa, 49, a Roman Catholic priest who works in this part of Mexico. “But the results are complicated.”