On the heels of several reports documenting U.S. citizens who have been detained or even deported by federal immigration officers, a top Homeland Security Department official in November issued a memo that aims to guide his agency on what to do when a person suspected of being illegally in the country claims to be a citizen.

(The memo can be seen here.)

John Morton, Homeland Security’s assistant secretary for Immigration and Customs Enforcement, sent the memo, which instructs ICE employees that “In all cases, any uncertainty about whether the evidence is probative of U.S. Citizenship should weigh against detention.”

(The memo supersedes a memo from November 2008, which superseded another memo from July 2008, which superseded a memo from May 2008.)

Aside from going deeper into the issue than previous guidance, the other differences are who issued the memo and to whom it’s addressed.

The memos from November and July 2008 were issued by James T. Hayes Jr., the then-director of ICE’s Office of Detention and Removal Operations, and sent to DRO’s field office directors.

Morton’s note didn’t just go to the deportation officers and enforcement agents assigned to DRO. The recipients include special agents (through the 26 special agents in charge) and ICE attorneys (through the 26 chief counsels’ offices). With it comes a sense of urgency and prioritization of such citizenship claims.

Morton’s directive also instructs agents and officers to work with the local U.S. attorney’s office to prosecute a person who lies about their citizenship claim.

(The government has shown its serious about prosecuting false claims, including asylum seekers.)

That the memo comes from Morton gives extra heft, and follows various media reports highlighting the issue.

CIR, in separate collaborations with the Los Angeles Times and Mother Jones, reported that numerous detainees with valid or possible claims to U.S. citizenship have been detained and even deported in recent years. (Other reporting on the issue can be found here, here and here.)

ICE’s new “Secure Communities” program that targets criminal aliens for deportation has also mistakenly identified thousands of U.S. citizens initially believed to be potentially subject to deportation.

More details on how ICE determines citizenship could become public through a lawsuit filed by one such U.S. citizen detained for seven months.

Vern Castillo, a native of Belize, became a naturalized U.S. citizen while he was in the U.S. Army. A few years after Castillo was honorably discharged from the military he ended up serving a short jail sentence following a domestic dispute with a girlfriend.

Instead of being released once his jail time was up, Castillo was detained by immigration officials who thought he was in the country illegally. An immigration judge didn’t believe Castillo’s protests that he was a citizen, and ordered the man deported. It was only after an appeals panel reviewed the case that immigration officials realized a mistake had been made in his file, and he was released.

Castillo filed suit in November 2008 against the agents. A federal judge in Tacoma recently ruled the case could move forward in part. The U.S. government has appealed that ruling to the 9th U.S. Circuit Court of Appeals. Settlement discussions are ongoing.

According to court records, Castillo (or his legal team) wants a lesson in how ICE agents and officers go about their business of determining whether someone in their custody is a U.S. citizen or not. They want to videotape a qualified operator showing them how database searches are conducted.

Among the things that could come to light are the policies, procedures and practices in determining, documenting and investigating citizenship and claims of citizenship. Castillo also wants to see the agency’s logs, training materials and manuals on the topic, court records show.

Andrew Becker is a reporter for Reveal, covering border, national and homeland security issues, as well as weapons and gun trafficking. He has focused on waste, fraud and abuse – with stories ranging from border corruption to the expanding use of drones and unmanned aerial vehicles, from the militarization of police to the intersection of politics and policy related to immigration, from terrorism to drug trafficking. Becker's reporting has appeared in The Washington Post, the Los Angeles Times, The New York Times, Newsweek/The Daily Beast and on National Public Radio and PBS/FRONTLINE, among others. He received a master's degree in journalism from UC Berkeley. Becker is based in Reveal's Emeryville, California, office.