AUSTIN, Texas — The return of a U.S. citizen who was deported to Mexico after a Central Texas traffic stop is putting new scrutiny on Texas’ fast-growing network of partnerships with federal immigration authorities, as local police and sheriff’s offices assume a larger role in immigration enforcement.

Brian José Morales García, 25, returned to the United States on Sunday after the federal government reached an agreement with his lawyers allowing him to reenter while litigation over his detention and deportation continues. Morales, who had been living and working in the Austin area, spent roughly four months in Mexico after authorities removed him in April.

Morales has maintained that he was born in Denver and is a U.S. citizen. According to reporting by The Texas Tribune, his attorneys provided federal authorities with additional evidence during the litigation, including a certified Colorado birth record, hospital records and witness affidavits. The Justice Department subsequently permitted him to return to the country. The agreement allowing his return does not by itself resolve his civil-rights claims or establish legal liability for the agencies and officials involved.

The dispute began with a traffic stop near Fredericksburg. Morales was riding with a construction crew when a Texas Department of Public Safety officer stopped the vehicle. Morales has said that he told officers he was an American citizen and that documentation, including his birth certificate and Social Security information, was available at his home in Austin. Immigration authorities nevertheless took custody of him, and he was later deported to Mexico.

The Department of Homeland Security previously disputed Morales’ account of his status, saying authorities had determined that he was unlawfully present in the United States. The agency did not provide The Texas Tribune with a new response to questions Sunday and Monday as Morales returned. The Justice Department, Texas Gov. Greg Abbott’s office and Texas DPS also did not respond to the Tribune’s requests for comment cited in its Sept. 2 report.

Morales’ federal lawsuit, filed in May in the U.S. District Court for the Western District of Texas, challenges his detention and removal and names federal immigration officials as well as unidentified Texas DPS and Gillespie County law-enforcement officers among the defendants. The litigation remains pending, meaning courts have not issued a final ruling on the legality of the actions at issue.

The case has gained broader significance because of the scale at which Texas law enforcement is now cooperating with ICE. Section 287(g) of federal immigration law permits ICE to delegate specified immigration-enforcement functions to state and local officers operating under agreements with the federal agency.

ICE currently describes three models for those partnerships. The Jail Enforcement Model allows participating officers to identify and process removable people already held in local detention facilities. The Warrant Service Officer program authorizes participating personnel to execute certain administrative immigration warrants in their facilities. The Task Force Model gives designated officers limited immigration authority while they perform routine police duties or participate in ICE-led operations.

That final model is drawing particular attention in the Morales case because it brings immigration enforcement closer to everyday policing encounters such as traffic stops. ICE says participating officers receive training in immigration law, multicultural communication and avoiding racial profiling and operate with federal oversight.

The Texas Tribune reported Sept. 2, citing the latest ICE statistics, that 432 Texas law-enforcement agencies have signed a combined 514 agreements under the program. Of those agreements, 314 involve the Task Force Model. The Texas Department of Public Safety and the Gillespie County Sheriff’s Office, whose deputies responded during the stop involving Morales, are among Texas agencies participating in the program.

The expansion has been rapid. The Tribune reported that roughly one month into Trump’s second term, only 28 Texas law-enforcement agencies had an ICE partnership. Texas has since become one of the states most deeply involved in the administration’s strategy of using local agencies to increase federal immigration-enforcement capacity.

State policy has reinforced that shift. Legislation approved by Texas lawmakers requires sheriffs in larger counties to request and, when offered, enter into agreements with ICE under Section 287(g) or a similar federal program. Supporters have argued that formal cooperation gives local departments training, clearer authority and federal assistance while helping identify people who may be removable under immigration law.

Critics have focused on the potential for mistakes when immigration questions enter encounters handled primarily by local police. Immigration law can involve complicated questions of citizenship, derivative citizenship, documentation and conflicting identity records. Morales’ case included records from both the United States and Mexico, and his Mexican identification contained discrepancies in the spelling of his first name and his date of birth, according to earlier Tribune reporting.

His attorneys say those discrepancies did not change the underlying evidence that he was born in Colorado. Before his deportation, Morales had also previously entered the United States through El Paso after presenting his birth certificate to U.S. Customs and Border Protection, the Tribune reported.

Civil-rights and immigrant-advocacy organizations argue that the expanding local role creates additional risks of profiling and erroneous detention, particularly when officers encounter people who speak accented English, primarily speak Spanish or cannot immediately produce citizenship documents. U.S. citizens generally are not required to carry passports or proof of citizenship while going about ordinary activities inside the country.

Supporters of 287(g), including ICE, present the program as a way to strengthen public safety and improve coordination between federal and local agencies. ICE says state and local officers participating in the program operate under federal supervision and are trained before exercising delegated immigration authority.

Morales’ experience now places those assurances against a concrete case in which a man with a U.S. birth record was removed from the country and later permitted to return after further documentation was presented. The unresolved lawsuit could determine more about how responsibility is divided among local officers and federal immigration authorities when citizenship claims arise during enforcement.

For Texas, the policy debate is likely to extend beyond one case. The state has invested heavily in immigration enforcement while the federal government has increasingly relied on local agencies to expand its reach. As those partnerships become a routine part of policing, Morales’ deportation is focusing attention on whether the system’s verification procedures and legal safeguards are keeping pace with its rapid growth.