Lawyers representing the wife and children of the man charged with attacking an event honoring Israeli hostages sued the U.S. government on Wednesday, seeking to release the family from custody and block their deportation, according to a court filing.

Hayam El Gamal, the wife of Mohamed Sabry Soliman, the Egyptian man accused of throwing Molotov cocktails at a crowd in Boulder, Colo., on Sunday, was arrested on Tuesday along with her five children by Immigration and Customs Enforcement officials.

The lawsuit was filed by Ms. El Gamal’s immigration lawyers and others seeking to help the family. The suit says that Ms. El Gamal and her five children entered the United States on tourist visas in 2022. The children are between 4 and 17 years old, according to the lawsuit.

The filing, in Federal District Court in Colorado, said that Ms. El Gamal “was shocked to learn” that her husband “was arrested for having committed a violent act against a peaceful gathering of individuals commemorating Israeli hostages.”

Kristi Noem, the homeland security secretary, said her agency would be investigating what the family knew about the attack before it happened.

“Today the Department of Homeland Security and ICE are taking the family of suspected Boulder, Colo., terrorist and illegal alien Mohamed Soliman into ICE custody,” Ms. Noem said on social media on Tuesday.

Later that day, the White House indicated in a social media message that the family could be deported imminently. On Wednesday, the Department of Homeland Security said that ICE was “processing Soliman’s family members for removal proceedings from the U.S.”

The filing on Wednesday said Ms. El Gamal was a network engineer who has lived in Colorado Springs for nearly three years and had applied for a U.S. work visa. Her husband, Mr. Soliman, also entered the country in 2022 with a tourist visa and quickly applied for asylum. His visa expired in early 2023, U.S. officials said, but he overstayed it.

The lawsuit says that the family is part of his asylum application and that it is pending. It also includes emails that Ms. El Gamal purportedly sent to her immigration lawyer on Tuesday, the day she was arrested.

“Hi please call urgently Florence Colorado ice office,” one email reads.

Eric Lee, one of the lawyers representing Ms. El Gamal, said the family was being detained at a family detention center in Texas.

The lawsuit requests that a federal judge order the release of Ms. El Gamal and her family.

“Punishing individuals for the alleged actions of their relatives is a feature of premodern justice systems or police state dictatorships, not democracies,” Mr. Lee said in an interview. “The detention and attempted removal of this family is an assault on core democratic principles and should provoke widespread opposition in the population, immigrant and nonimmigrant alike.”

Stephanie Saul contributed reporting.