Grieving mum steals baby from US shopping mall

US authorities have released security footage of a grieving mother stealing another woman's baby from a shopping mall.

Cherie Amoore, 32, struck up a conversation with Malika Hunter, who was shopping with her two-year-old son and seven-week-old infant in the King of Prussia Mall on March 31.

"She was so polite," Ms Hunter told NBC. "Nice, calm and energetic. Like the normal, average person."

But when Ms Hunter was momentarily distracted by her older boy, Amoore picked up baby Ahsir Simmons and briskly walked away.

The newly-released footage of the abduction shows her exiting the mall directly, seemingly resisting the urge to break into a run.

The mall was locked down and an amber alert issued after a frantic Ms Hunter reported the crime, but it wasn't until about 10.30pm that Ahsir was recovered, some five hours after he was taken.

"I don't know why I did it," Amoore, who said her baby died just hours after he was born on February 11, allegedly told police.

"I can't explain it. I held him, and all those feelings rushed back. I just wanted my baby. I felt like I was holding my son again. It felt so good. I didn't want to lose that feeling. I was crazy. I never intended to do anything like this."

Amoore, who was granted bail after an initial hearing, is yet to be tried for the crime.