COLORADO SPRINGS, COLO. -- Maritza Rentz was facing the prospect of a third divorce last June when she told her husband that she was expecting a baby.

The news buoyed the marriage but, when Rentz's pregnancy was medically terminated in October, she reportedly hid the fact from her husband, marking the start of what police describe as an "elaborate scheme" of deception that would culminate in the abduction of another woman's infant daughter.

Rentz, 38, a psychotherapist who bore two children in a previous marriage, faces charges of second-degree kidnaping and, one week after the incident, police say they are still sorting the details.

Until his wife's arrest and the safe return of the infant Tuesday, Air Force Capt. Paul Rentz, a behavioral sciences instructor at the Air Force Academy here, believed that the baby who arrived at their home after what would have been a nine-month pregnancy was theirs, police said.

Colorado Springs Police Capt. Victor B. Morris said Rentz, on her doctor's advice, had an abortion last October but took steps to make sure that her husband would not find out.

"She had an attorney contact the hospital to prevent them from telling her husband the pregnancy was terminated," Morris said. "She hid the fact by stuffing pillows under her dress and would not let her husband see her naked or engage in sexual activity."

"While she was with him," Morris said, "she would go through this act of being pregnant. But while he was at work, she would take the pillows out and go about her normal day."

Rentz ran a psychotherapy practice, specializing in mother-daughter and family counseling, and wrote columns for Hispania, a biweekly newspaper here, according to Bob Armendariz, its editor and publisher.

Capt. Rentz, 36, had never been a father and believed his wife when she told him that she had delivered the baby at a hospital at 9:42 a.m. last Friday and that she driven herself and the child home six hours later, police said.

That was the day that Rachael Ann White, born Jan. 18, was kidnaped from her mother's home by a woman who answered an advertisement seeking a baby sitter.

Police said the baby's grandmother was interviewing the woman when the phone rang in another room. She handed the baby to the woman and returned two minutes later to find that both had disappeared, they said.

Cora Abbott, the infant's mother, issued a

nationwide plea for help, and the search began.

On Tuesday, police said they were called by Capt. Rentz's supervisor, who told them that the baby he had seen at the Rentz home the night before appeared to be several weeks old, not newborn, as the couple had described her.

Police said they went to the home and, seeing a car that matched the description of the one driven by the abductor, asked Capt. Rentz if they could talk to him and his wife.

"You're going to have to be quiet because there's a newborn in the house," he reportedly told them.

Upstairs, in a nursery containing child-care books and a dresser full of infant clothes, police said they found Rachael Ann White, the clothes she was wearing when abducted, a fake birth certificate and a map with her neighborhood circled.

Police released Capt. Rentz, saying they have no evidence that he took part in the incident.

News of the incident startled Maritza Rentz's father, a San Antonio physician who emigrated with his family from Cuba 21 years ago.

In an interview with the Colorado Springs Gazette Telegraph, Jorge Beato said, "She called us in November or December and told us we were going to be grandparents again." He said she called after the child arrived to ask his advice on the type of formula she should feed her.

Dr. John Macdonald, a psychology professor and director of forensic psychology at the University of Colorado Health Sciences Center, said similar cases are rare.

"Often . . . there's elaborate deception, using padding for the stomach, holding baby showers and similar things," he said. "If you can hide a pregnancy, you can fake a pregnancy, and there's a tendency to believe rather than be skeptical when someone tells you they're pregnant."