Southaven, Miss. ? A car ran a police checkpoint outside an arena where President Bush had spoken and rammed the building Saturday. Authorities swarmed the car with weapons drawn and took away the driver and her three children who were with her.

Bush was in his limousine when the incident happened, but the limo had not left the building, and he was not hurt, a senior Bush administration official said. Bush left the arena less than five minutes later from an exit about 40 yards from the car.

Secret Service and local law enforcement investigators concluded after interviewing her that she had no intention of harming the president, said Ann Roman, a Secret Service spokeswoman.

“Essentially, she was trying to locate her mother-in-law, who was attending the president’s speech,” said William Jenkins, the FBI’s acting special agent in charge in Jackson.

The woman, who was not carrying any weapon, was arrested for trespassing, Roman said in Washington, D.C.

A law enforcement official, speaking on condition of anonymity, identified the driver as Betina Mixon, 29.

Friends of the Horn Lake woman said she “snapped” under recent stress but that they did not believe the incident was politically motivated.

Witnesses said a gray Toyota Camry drove through a parking lot on the same side of the DeSoto Civic Center as the president’s exit. The car jumped the curb, drove through a gate where press buses had just left and rammed the building near a loading dock.

“We heard sirens and looked and the car was flying around the corner,” said Michael Smith, 17, who was on the loading dock with about a dozen workers taking a break from their food service jobs at the center.

“As soon as the car hit the wall, there were probably 20 cops on her,” Smith said.

Damage to the front of the car indicated it hit the building at 5 to 10 mph. No ambulances were called.