A group of migrants was asleep when men with guns burst through the door of the shelter they were staying at in Nogales, Sonora, witnesses said.

“They broke down the door and using bad words, told us to get up,” said a 53-year-old from Guadalajara, Mexico, who asked not to be identified for fear of retaliation. “They put us face down and went through our pockets. They got my wallet and took 800 pesos (about $60).”

Twenty migrants, mostly from Central America, were staying Thursday night at La Roca, a popular Christian shelter for Central Americans trying to get to the United States or who were just deported.

The armed group included 19 men in ski masks and a woman who appeared to be leading the operation. They wore police uniforms and were riding in at least eight marked patrol units, said the Kino Border Initiative group in a news release.

Aldo Saracco, first inspector of the state commission of human rights in Sonora, said Saturday he could not confirm if the gunmen were members of the state and municipal police because it was too early in the investigation.

A call and emails to Nogales and Sonora state police went unanswered Saturday. Rights groups have filed complaints with Mexican state and federal authorities, as well as with state and federal human rights commissions.

“We want to know exactly what happened so police don’t feel they can do whatever they want,” said Marla Conrad, an advocate with the Kino Border Initiative, a binational organization that works on immigration issues in both sides of the border.

The group is helping the seven men who came forward to file an official complaint and is assisting the family that runs the shelter.

Saracco confirmed the agency received a formal complaint and is working with authorities, who have 15 days to respond.

Migrants making the journey north are often prayed upon by criminal organizations or in some cases by the authorities themselves. Central Americans are particularly vulnerable, experts and officials say.

“It is something that has always existed, but people are afraid to report it,” Saracco said. “They fear deportation and come with the idea that they have to put up with everything in order to fulfill their dream.”

The commission has received reports of incidents in the Benjamin Hill area, about 90 miles south of Nogales, he said, where the train tracks cross and migrants get off one train to either head to Nogales or to Altar. About two years ago they had an incident involving Honduran immigrants who were taken by municipal police officers to a nearby ranch to be extorted. Four officers were imprisoned for extortion and kidnapping, while one remains at large, he said.

In Thursday night’s incident, Conrad said, the armed men went through the immigrants’ belongings, taking their money and cell phones, before locking them in a room and threatening to deport them. After approximately 90 minutes the group left.

Shelter residents called the city’s emergency number for help, but instead of aid the original group returned.

They came in and asked who made the call, the migrant from Guadalajara said Saturday in a telephone interview. When they refused to say, the intruders took a picture of every migrant at the shelter and said they would be beaten or killed if any of them talked.

“Many of the immigrants left immediately because they were afraid,” the man said. He decided to stay to report the crime and was threatened again Saturday morning as he left the comedor, a space where the Kino Border Initiative feeds migrants near the border.

“Don’t you understand that you have to leave or we will kill you?” the man said he was told by men in a white pick-up truck.

Conrad said local and state authorities have been helpful in responding to the claims, but have provided no security measures to protect the immigrants who filed the complaint or to the family that runs the shelter.

The family, which includes six children, is originally from El Salvador and was threatened with deportation even though they have Mexican resident status.

Members of the Kino Border Initiative are working to move the migrants to other locations as soon as possible.

“We need everyone to be watching so this doesn’t happen again,” she said, “and so that the family is not retaliated against.”

Star reporter Luis F. Carrasco contributed to this report.

Contact reporter Perla Trevizo at ptrevizo@tucson.com or 573-4210. On Twitter: @Perla_Trevizo