Detroit police said Leola Brock-Reese wasn't home at the time of the burglary, but her 57-year-old neighbor was and saw men breaking into the home through her window.
When the thieves noticed the woman watching them, one of them fired a shot into the woman's living room.
The bullet shattered the living room window, but barely grazed her skin.
Police said it was the underwire in her bra that deflected the bullet.
"Well I was thinking that I should buy more underwire bras," joked robbery victim and homeowner Brock-Reese.
"A miracle bra, yes. That's what saved her life," said Rochelle Wicks, another neighbor.
The woman's daughter, who is also a Detroit police officer, said her mother's minor injuries are from the broken glass.
The thieves did take several items from the house.
Police said they are looking for three black teen males between 16 and 18 years old.
They were seen leaving in a burgundy Dodge Neon.