Updated

A 13-year-old girl caught shoplifting was locked up with adults in a Texas county jail for almost two weeks before authorities realized she was a minor, police said.

The teenaged runaway was arrested July 10 at a Target department store and was taken to the Dallas County Jail. The officer who took her into custody said he found no record of her and assumed she was 17, according to police Sgt. Warren Mitchell.

An internal affairs investigation has been launched to review the matter, Mitchell told The Associated Press Thursday night.

The girl had no identification with her and gave a false name and age, he said.

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The arresting officer attempted to contact the police youth division to confirm the information but couldn't track the teen down, according to Mitchell. He didn't say why the officer concluded the 13-year-old was 17.

The girl was released from custody July 23 after appearing before a judge and is again listed as a runaway.

Meanwhile, an inmate, an acquaintance of the girl's family who had recognized her, phoned her father, who came to police with a birth certificate and other records verifying her real identity and age.

He said investigators want to find out whether the officer who made the arrest followed policy, and what could be done to prevent the situation from happening again.

The officer who made the arrest, Sr. Cpl. Roberto Garcia, told The Dallas Morning News that the information that the girl provided him would have made her an adult.

"It's just the frustrating battle that we have out there in the real world," Garcia told the newspaper. "I just have a heck of the time when these juveniles won't tell you who they are and they have no ID."

Assistant Chief Ron Waldrop, who heads the department's investigations bureau, told the paper that the girl initially identified herself as being 14, which he said should have raised concerns.

"Everybody believes that should have required an intense level of checking before incarceration," he said.

The Associated Press contributed to this report.