Concerns were growing Sunday over a local activist who disappeared after making a chilling plea for help on Facebook live.

SAN DIEGO (CBS 8) — Concerns are growing over a local activist who disappeared after making a chilling plea for help on Facebook live.

Family and friends say they haven't seen Hugo Castro since he posted the live video near Mexico City on Thursday.

The video shows Castro pleading for help on the side of a highway, in it he said there were criminals chasing him who wanted to kill him. For friends, the video is hard to watch.

"We don't know all the details, we know it's a very unfortunate situation, we're very concerned, this is actually the sixth vigil we've done for him," said founder of Border Angels Enrique Morones.

Castro is a volunteer with the San Diego-based advocacy group Border Angels. Morones said he was part of a caravan helping migrants make the trek from Central America to the U.S.-Mexico border.

"There are a lot of people who are very concerned about him because he's one of our leaders, great friend," said Morones. "I'm actually the godfather of his baby."

Morones said details are few and far between right now. In the meantime, he has held several vigils for his friend, the latest was held Sunday afternoon in Chicano Park.

"He's one of those people that even if he doesn't know you he's always kind of helping, always stands up for injustices and things he sees," said Dulce Aguirre.

In his Facebook live post, Castro said he was out of money and couldn't trust the police. Friends say they haven't heard from him for several days now.

"I was very worried just because he's by himself," said Aguirre. "And he's not very familiar with where he is - so I was very worried when I saw it."