After being separated under the Trump administration's now discontinued "zero tolerance" policy — which led to children in more than 2,700 migrant families being separated from their parents — Lilian Martinez, 25, and her 5-year-old son reunited in June 2018.

They are now at risk of being separated by the U.S. government — again.

The boy, Wanner, has been issued a deportation order for missing a court date, while his mother, a native of Guatemala, can stay in the U.S. while her asylum case is pending. Their attorney Mana Yegani told CBS News the family was not informed of Wanner's scheduled court appearance.

Lilian Martinez, 25, a native of Guatemala, and her five-year-old son, Wanner, came to the U.S. last year. Mana Yegani

"For me, it is very difficult. I don't want to go through that again," Martinez told CBS News during an interview in Spanish Thursday, referring to the approximately two months she and Wanner spent separated under the "zero tolerance" policy last year.

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"I was forced to leave my country. Going back to Guatemala is not an option," the young Guatemalan mother added, stressing that she received deaths threats there.

Yegani, the attorney, said she only found out about Wanner's deportation order on Wednesday when she called a court hotline to check on the status of the case. A copy of the order reviewed by CBS News is dated April 11.

A spokesperson for the Justice Department's Executive Office for Immigration Review, which adjudicates all immigration cases in the country, confirmed that a judge issued an order to remove Wanner from the U.S. on April 11. All parties in the case have 30 days to appeal the decision before the Board of Immigration Appeals, the spokesperson added.

"So, now, the 5-year-old boy has an order of deportation, with an arrest warrant," Yegani added. "And you know, if ICE wanted to come and take the baby, they could. I mean, they haven't yet. And I'm not going to let that happen."

She said she began representing the family on a pro bono basis last year after helping Martinez reunite with her son, who had been placed in foster care by immigration authorities. Since then, the attorney said, she has been to court twice to represent the Guatemalan mother in her ongoing asylum case.

When she noticed the cases for Martinez and Wanner were separate, Yegani said she urged the judge in the first court appearance to merge them into one. "I took the little boy with me to court, even though he did not have a court date," she said. "And I told the immigration judge, 'Your honor, this baby does not have a court date, but his mom has a court date.'"

Yegani said the judge responded by saying the problem was not her "responsibility" and that she could not give the child a court date. She said the judge indicated it was a matter for Immigration and Customs and Enforcement (ICE) officials to handle.

"This is kind of a trend that is happening, where these kids are getting court dates that is not the same court date as their parents," Yegani said.

"How can you order a 5-year-old deported when his mom has court August 5?" she added. "It just shows what a cluster mess the immigration court system is."

She said she believes the "trend" is immigration authorities not linking the cases of some migrant children who were in foster care with those of their parents once the families were reunified in the aftermath of "zero tolerance." She said in another case she's handling, the parents have court dates but the children don't.

Last week, facing massive public outcry, a federal judge halted the deportation of an 11-year-old Salvadoran girl after she was ordered removed without her mother and 15-year-old sister, TIME reported.

Yegani said she filed a motion to reopen Wanner's case on Thursday in an effort to halt his deportation.

Angel Canales contributed to this report.