Emily Samantha Ruiz, age 4 and a U.S. citizen, was returning to the U.S. with her grandfather after visiting relatives. He was detained and she was deported back to Guatemala.

"I'm just shocked," the family's lawyer, David Sperling, said Tuesday.

"I think it's an outrage that Customs and Border Protection didn't do anything to reunite her with her parents....She is a U.S. citizen and she has every right to come to the U.S."

Emily Samantha Ruiz and her grandfather, who had a work visa allowing him to travel, were returning from seeing relatives March 11 when their New York-bound plane was diverted to Washington.

Officials at Dulles Airport noticed an illegal entry from the 1990s on grandpa's record and took him into custody, Sperling said.

He suffered what Sperling believes was a panic attack and was sent to the hospital. The lawyer declined to name the grandfather.

Emily was in federal custody for nearly a day in the airport while her parents in Brentwood wondered why the pair hadn't arrived home as planned.

When her father figured out what happened and spoke to a border control agent, the lawyer says, he was told he had two choices: Emily could be held at a juvenile facility in Virginia or return to Guatemala with her grandfather.

Worried she would be put up for adoption, he chose the latter option and has been trying to get her back ever since.

A Customs and Border Protection spokesman confirmed Emily was sent back but would not comment on her case further.

He said agents are instructed to tell parents in similar cases they can pick up their child, have the child turned over to child protective services or have the kid sent back to the country they left.

"We take every effort to reunite minors with their parents," said Steve Sapp. "The parents need to make the decision."

But he conceded undocumented parents like Emily's risk being detained if they show up. "They do have to face consequences," he said.

Rep. Steve Israel (D-L.I.) is asking Homeland Security to conduct a review.

"This bureaucratic overreach and utter failure of common sense has left a little girl - a U.S. citizen no less - stranded thousands of miles from her parents," he said.

Meanwhile, Sperling plans to have a staffer go to Guatemala and retrieve Emily.

"We hope there's a happy ending to this story," he said.