A Brooklyn Park man kept the mother of his three children captive in a car for six to seven hours Wednesday, circling the Twin Cities while threatening to kill her and their youngest child, authorities say.

At one point, the woman pressed her face against the window and mouthed "Help me!" to another driver, according to charges filed Friday against Chia Vang, 27.

He is scheduled to appear Monday in Ramsey County District Court, charged with one count of kidnapping, two counts of terroristic threats and one of methamphetamine possession.

The victim, identified as M.V., told police that Vang was her ex-boyfriend; he said they were married in the Hmong tradition.

According to the charges, M.V. had stayed in domestic-abuse shelters after Vang allegedly head-butted and choked her in their home last week.

The woman, 29, asked her nephew to pick her up to run errands Wednesday, and as they rode with the couple's two oldest children, they noticed Vang following them in her car. He had learned of her whereabouts by looking at the caller ID on her mother's phone, he later told police.

The woman called 911 from a St. Paul market, and police arrived to speak with Vang. Police sent him and the couple's youngest child away on foot after learning that an order for protection that the mother had sought was not yet valid, authorities say.

Vang reappeared, threw the couple's youngest child into the mother's car, blocked in the nephew's vehicle and forced M.V. into the car.

During the drive, he threatened to pick up the other two children to "kill them all in a car crash," the complaint states.

He was arrested in Washington County. M.V. and the child were not hurt.