Mesa Police Department officials said Powell's nanny Kaitlyn McGrath and son Cash Powell were able to flee the vehicle before gang member Jasper Stewart rode off in it Friday.
Kaitlyn said the gang member -- who police say has a detailed criminal record -- threatened to kill her when he got in the SUV.
"I just knew that I had to get Cash out," McGrath told azfamily.com.
Stewart, 31, was apprehended by Mesa police with the help of OnStar technology and an iPad app a few miles from the scene of the carjacking.
Chris's wife Heidi said that she "couldn't help but be anything but grateful" Kaitlyn put her life at risk to save Cash, 1.
"How easy would it have been for her to just jump out, scared for her life, and forget about Cash?" she said.
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