Verna McClain, 30, is accused of fatally shooting Kala Golden Schuchardt Tuesday in the parking lot outside pediatric clinic in Spring, Texas, and then taking her 3-day-old son, Keegan, and fleeing the scene.
After being tracked down by detectives, McClain confessed to the shooting and abduction of the baby, authorities said. Keegan was found alive in McClain's apartment.
Montgomery County District Attorney Brett Ligon said the shooting and kidnapping seemed to be part of a plan hatched by McClain, a nurse who had recently suffered a miscarriage, the Houston Chronicle reported.
"There were statements as indicated in the arrest record that were made by Ms. McClain that led us to believe that, in fact, this was an intentional act on her part. Not that Ms. Golden was targeted specifically, but that this was part of a plan to kidnap a child," he said.
Authorities said they believe McClain intended to kidnap a child to pass off as her own.
The suspect's family say she is not a violent woman.
"She's not a violent person, so for her to shoot someone, it was shocking," said McClain's estranged husband, Theo McClain, 34. "This is all crazy to me."
"I don't know what's going on -- that's not my kid," Verna McClain's mother said Wednesday. "But I'm sorry for the family."