A Chinese woman detained by U.S. border officers for overstaying a visitor visa died by suicide while being held at a border patrol station in Arizona, a Democratic congresswoman said.

The woman had been taken into custody in California after officers determined that she had overstayed a visitor visa, Representative Pramila Jayapal of Washington said in a statement, citing the U.S. Customs and Border Protection agency. She was transferred to a patrol station in Yuma, Ariz., the statement said.

Ms. Jayapal, a ranking member of the House subcommittee overseeing immigration, said initial reports from the agency had raised concerns about whether officers had properly conducted welfare checks on the woman. While welfare checks were logged, officials at the agency investigating the death could not verify whether the checks had actually happened, Ms. Jayapal said.

“There is no excuse for why agents cannot verify if some of the necessary welfare checks occurred — or why some of the documented welfare checks were incorrectly reported,” Ms. Jayapal said, adding that she was concerned about the conditions in facilities where immigrants are detained.

“Another preventable death only increases that concern,” she said.

The woman had been in the country on a B-1/B-2 visa, according to the statement, a temporary visa for people visiting the United States for tourism or business.

“All in-custody deaths are tragic, taken seriously, and are thoroughly investigated by C.B.P.,” a spokesman for the agency said in a statement on Friday, adding that the agency was investigating the woman’s death.

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