LOS ANGELES—A Texas man has pleaded guilty to kidnapping a 13-year-old girl who was rescued in Southern California when a passerby saw her hold up a “Help Me!” sign in a parked car.

A statement Jan. 19 from the U.S. Attorney’s Office in the Central District of California said Steven Robert Sablan, 62, of Cleburne, Texas, admitted in a plea agreement that he sexually assaulted the victim while driving her from Texas to California.

The girl was rescued July 9 in Long Beach, south of Los Angeles, after a passerby called 911 to report seeing her hold up the piece of paper with the handwritten desperate plea for help.

Mr. Sablan, who has been in federal custody since July 2023, pleaded guilty to one count of kidnapping, prosecutors said.

His attorney, Deputy Federal Public Defender Nadine Hettle, declined to comment Saturday.

In July, Mr. Sablan was indicted by a federal grand jury on charges of kidnapping and transportation of a minor with intent to engage in criminal sexual activity.

An FBI agent wrote in an affidavit supporting the criminal complaint that the girl was walking down a street in San Antonio on July 6 when Sablan drove up, raised a black handgun and told her, “If you don’t get in the car with me, I am going to hurt you.”

A sentencing hearing was set for Oct. 25. Sablan will face a mandatory minimum of 20 years in federal prison and a maximum sentence of life.