Suspicious officers immobilized her, jammed cell phone signals that could detonate the explosives, then carefully removed her suicide vest.
She turned out to be just 15 years old, and her story is an increasingly common one.
She comes from Baquba, an al Qaeda hot spot just north of Baghdad. It's a recruiting ground for women suicide bombers who are responsible for much of the recent carnage in story=3220766>Iraq.
Last year, there were eight women bombers. So far this year, there have been 35. A CBS News crew traveled to Baquba to meet Rania in jail.
"I now thank God that I didn't get blown up," she said through a translator.
Rania told police she had no idea the vest was a bomb. Family members, including her husband, she said, had helped her put it on.
Police think they may have drugged her, and meant to blow her up by remote control.
Rania said through a translator: "They told me that it was a kind of medical vest for back pain."
Gen. Abdul Kareem Qalaf helped interrogate Rania. He said: "She has a low IQ and is a vulnerable teenage girl."
Why does there suddenly seem to be so many women suicide bombers?
Qalaf said through a translator: "Al Qaeda uses these people - the mentally ill, children and very young women. This shows al Qaeda is failing."
As for Rania, she lived to tell a tale that helped police arrest her husband. But her aunt, the suspected ringleader, is still on the run. She's one of a new breed of Iraqi women turned into key players in the ruthless business of terrorism.