After broadcasting a desperate plea on Facebook, a U.S. immigrant activist went missing in Mexico. But now he’s been found

Standing on the shoulder of a busy Mexican highway, Hugo Castro hit “record” on his smartphone and issued a desperate plea.

“They want to kill me,” he said. “I really need help.” A group of criminals had been chasing him for days, he explained in a 20-minute video he broadcast on Facebook Live on Thursday.

Castro, a U.S.-born immigrant activist, hadn’t been heard from since, prompting a cross-border search campaign by his friends and family.

On Tuesday, he was found alive, according to a message posted on Facebook by his partner, Gaba Cortes. “That is what we can share,” Cortes wrote. “We thank all those who intervened.”

What exactly happened to Castro — and whether the threats against him were real — was still unclear Tuesday. But the case generation considerable attention on both sides of the border given Castro’s work with immigrants and the recent troubling history in Mexico of los desaparecidos, people who disappear without a trace.

Castro, 54, worked for a decade in the San Diego and Tijuana area with a well-known migrant advocacy group called Border Angels. Castro often left water in the desert to help those making illegal and dangerous treks across the border, and in recent months, he had started working with the large community of Haitian migrants who have been stranded in Tijuana since the U.S. changed its immigration policy toward them.

Castro had received threats in the past from human smugglers, said Enrique Morones, director of Border Angels, who on Monday said he was worried that Castro had again been targeted.

Morones said he last saw Castro this month in San Diego, where, over dinner, Castro explained that he wanted to travel to southern Mexico so that he could head back to Tijuana with a caravan of Central American asylum seekers to raise awareness about their experience trekking toward the U.S. Morones said he gave Castro some money for the trip and then drove him to the Mexican border.

Castro, a father of four, who in recent years has called Tijuana home, later took a bus from Tijuana to another city in northern Mexico, where he met up with fellow activists. They planned to drive in a car together south to the state of Chiapas, on the border with Guatemala.

But the car had mechanical problems, Morones said, and Castro somehow became separated from the group. In the video he recorded on the side of the highway, near the central Mexican city of Puebla, Castro said he had run out of pesos and nobody would accept his U.S. dollars.

In the video, Castro walked along the highway as cars whipped past him and the early-evening sky darkened with storm clouds. He repeatedly explained his location, at times appearing to ramble.

He said that he had been cornered by truck drivers associated with a criminal group from the northeastern state of Tamaulipas and that the police were of no help.

“I need help,” he said. “I need help.”

The circumstances of Castro’s disappearance, and the odd nature of his final video, have led some to speculate whether his disappearance might have been linked to mental health issues or other problems.

Morones said he wasn’t aware of Castro’s suffering mental health or other problems, although he noted that Castro did live with high levels of stress.

“He’ll work 18, 19 hours,” Morones said. “I told him, ‘Don’t do it at that pace.’ ”

According to family members, Cortes, Castro’s partner, traveled to Mexico City to file an official complaint with prosecutors Tuesday. In a post on her Facebook page that day, she described Castro’s disappearance as part of a larger trend of forced disappearances in Mexico, where by the end of last year 30,000 people were missing, according to the National Human Rights Commission, a government agency.

“In a country of the disappeared, we will not allow Hugo Castro to be one more,” Cortes wrote. “We are missing Hugo, and we are missing the 43,” she said, referring to the 43 students from the town of Ayotzinapa who vanished without a trace in 2014.

kate.linthicum@latimes.com

Twitter: @katelinthicum

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UPDATES:

3:25 p.m.: This article was updated to report that Hugo Castro has been found in Mexico.

This article was originally published at 11:55 a.m.