California activist missing in Mexico after posting plea for help on Facebook

SAN DIEGO - A San Diego activist has not been seen since he posted a video on Facebook asking people for help while in Mexico, authorities said Monday.

Hugo Castro was participating in a migration caravan assisting people to Tijuana when he was stranded on a highway, in-between Mexico City and the city of Puebla.

In the Facebook Live video, Castro explained he was being followed and feared for his life. Castro hasn't been heard from since this video.

"He's had death threats in the past. The last one was three weeks ago," said Enrique Monroes, the director of Border Angels, an immigrant activist group.

Casto's family has alerted the Mexican and United States consulates and are praying for his safe return.