"Pettway is sorry and she knows that she has caused a lot of pain," the complaint states.
In her confession, Pettway offered details of how she took Carlina. She says she saw the 19-day-old baby at the hospital on Aug. 4, 1987, slipped into her room a few hours later and took her.
"When no one stopped Pettway she took the victim with her on a train to Pettway's home in Bridgeport, Conn.," the complaint says. "She told her friends and family members that the victim was her child."
As Carlina, who then became known as Nejdra Nance, grew up, she lived with Ann Pettway at times and at other times with Pettway's mother, Mary, who also lives in Bridgeport, according to Ann's confession.
She says she tried to create a fake birth certificate for Carlina but was never able to create one that appeared real.
Pettway faces federal kidnapping charges. Three of Pettway's family members were with her in Manhattan Federal Court on Monday to lend their support.
Robert Baum, Pettway's public defender, tells PEOPLE he first met his new client Monday morning and she was tearful during the interview. "She's pretty upset, but she understands what's going on," Baum says. "She became aware of the police chasing after her because of press accounts."
The attorney confirmed she turned herself in and says she faces life in prison. Pettway will not have to enter a plea at the arraignment later Monday and he says he will not ask for bail.
Asked about her confession to the FBI, Baum says, "It's alleged she made those statements. I will investigate her medical history, the miscarriages. She cares deeply about Carlina. She feels badly. She is very upset. She has expressed concern about her family, especially Carlina. She understands the gravity of the situation."