(CNN) A 9-year-old boy hit a car thief over the head with an iPad and his 16-year-old sister choked the thief and called 911 until he bailed out of the stolen SUV, police told CNN affiliate WGN.
The incident started outside a Domino's in the Chicago neighborhood of West Rogers Park on Sunday, police said.
The father of three children left the Toyota Highlander running as he went into the pizza shop and someone jumped in and drove off, according to police.
"I started shouting at him, 'Who are you? Get out of the car!' and he starts driving really fast down the road," the teenage sister, Imama Muratab, told WGN.
She said after she told the thief there was a baby -- her 4-year-old sister, Ayesha -- in the SUV, he told her to get out or he would shoot her.
Imama said the car thief was no older than 17. She said she didn't see a weapon, WGN reported.
Imama told the affiliate her 9-year-old brother, Hasnain, hit the offender over the head with an iPad. She was in the seat behind the driver and started to choke him, and then she grabbed her father's phone to call 911.
"Thirty seconds into the call, the dude just hopped out of the car," Imama told WGN. The incident covered four blocks, WGN reported.
The thief got into a stolen Toyota Camry that officers later spotted at a gas station. Four of the five people in the car were taken into custody. One person escaped, police said. They didn't say whether the car thief was one of the people detained.
The children were not injured, police said in a statement.