"Be careful! And may everyone come home safely!" With these words on Facebook, Martina Grifaldo begins her days, spent alerting her 171,000 followers of possible raids by Donald Trump's much-feared immigration police.

At dawn, after the usual greetings, this American of Mexican origin, head of the Alianza Latina Internacional association, asks the fateful question about the situation in the streets of Houston, the large city of Texas, the fourth most populated in the United States.

"We post emojis of an ice cube next to a police officer's emoji, asking people to help us by reporting" where they are, explains the 62-year-old notary born in this southern state, which has large communities of Latin American origin.

The police officer and the ice cube, a reference to the federal immigration police known as ICE, an acronym that corresponds to the word "ice" in English. For weeks, its rather burly and masked agents have been causing terror in Latino communities across the country, with mass arrests, sometimes very violent. Images that are making the rounds on social media.

- "At any time" -

President Donald Trump regularly denounces the presence of immigrants, whom he describes as "illegal" or even "criminal." However, according to human rights NGOs, the vast majority of people detained in detention centers have no criminal record.

These organizations accuse ICE of engaging in racial profiling, conducting raids on places frequented primarily by Latinos and targeting people who appear Latino.

Martina Grifaldo's followers regularly send her videos filmed with their phones, showing men sometimes without uniforms or arrest warrants.

"Every time we see how they treat them, we're a little terrified, because it could happen to us at any moment," says Francisco Mendoza, a 57-year-old plumber of Mexican origin, who works with the same association, Alianza Latina Internacional.

In July, the NGO Human Rights Watch accused the US authorities of treating people held in detention centers in a "degrading and dehumanizing manner," describing "conditions that constitute a flagrant violation of international human rights standards."

On this September day, Francisco Mendoza accompanies Martina Grifaldo in a van as they travel the roads, where they sometimes come across vehicles that appear abandoned and which turn out to belong to people who have been arrested.

- "Risks for us" -

Under their fluorescent yellow and orange caps, the two accomplices also keep an eye on the messages they receive. One of them comes from restaurant employees who invite them for a bite to eat as a thank you.

This is the restaurant where Elizabeth, a 35-year-old Salvadoran woman who is fighting to regularize her situation in the United States, where she arrived ten years ago with her son and mother, works.

"I take my hat off to them because they take risks for us. Thanks to them, we stay informed. I'm taking care of my mother who is sick, imagine if she's waiting for me and I don't come home," she says, serving snacks to Martina Grifaldo and Francisco Mendoza.

The latter admits to being "heartbroken": "We lived more or less in peace, we worked, we paid our taxes."

Because, he recalls, in the United States, "undocumented immigrants pay a lot of taxes, which are paid to various government departments, and we receive nothing in return, no help, contrary to what they say."

The patrol ends in the late afternoon. Martina Grifaldo concludes the day with a new message on Facebook: "It's difficult, but we have to rest. Tomorrow is another day where we will continue to resist."