By ELLIOT SPAGAT and VALERIE GONZALEZ

SAN DIEGO (AP) — A week before Chancely Fanfan was scheduled to attend an immigration court hearing in San Diego, he received a letter from the Department of Homeland Security instructing him to show up for what he thought would be a routine check-in with U.S. Immigration and Customs Enforcement after his hearing.

After the 31-year-old Haitian man showed up with his wife and 11-month-old baby to his court hearing and ICE check-in on Oct. 20, immigration officers arrested him, providing no reason other than that the government required it, his attorneys said.

Fanfan had no criminal history and showed up to all his court hearings and check-ins with ICE since his arrival in the U.S. last year, according to the petition filed Tuesday in the Southern District of California. The Center for Immigration Law and Policy and the Center for Human Rights & Constitutional Law are challenging the October detentions of Fanfan and two others following their check-ins with immigration officers.

“Petitioners have had no criminal contact since their prior releases from DHS custody, and two petitioners have no criminal history of any kind,” according to the petition.

The petitioners were detained after entering through or between U.S. ports of entry when they came to the country. After vetting, they were released from federal custody.

The lawsuit alleges immigrants are being deprived of due process after previously being declared fit for release, only to be arrested and detained when suddenly summoned to reappear at an ICE office. Many cases involve people whose cases in immigration court were reopened.

The Department of Homeland Security did not respond to an email seeking comment Tuesday.

The UCLA School of Law’s Center for Immigration Law and Policy said the detentions in San Diego alone “are certainly in the dozens, and likely exceeds 100.” The lawsuit is asking the judge to certify the class, which could mean that others who were arrested and detained in similar circumstances could benefit from a favorable ruling.

A gardener from Mexico who has lived in the U.S. for more than 30 years sat on the floor of a long hallway outside a packed waiting room at ICE’s San Diego office on Monday. He spoke to The Associated Press on condition that only his first name, Lorenzo, be published because he feared potential consequences.

About 10 years ago, Border Patrol arrested Lorenzo at a highway checkpoint in Southern California. He went before an immigration judge who closed his case and spared him from being deported. For years, he had heard nothing from immigration authorities until last week, when he was told his case was being reopened and that he was to report to ICE on Monday. He didn’t follow up with the AP after his check-in.

Arrests at ICE check-ins appear to have accelerated since early October in San Diego. Lynn Devine, a volunteer observer, saw one woman who checked in being escorted to an elevator in handcuffs by two officers on Monday.

“She was looking at the floor. I told her I was praying for her,” Devine said.

A federal judge will be deciding whether to release the three petitioners and whether to declare such detentions unlawful.