Sharon Rector, the 20-year-old woman charged with kidnaping a baby boy last Friday, cared for the infant "like it was hers" and showed him off to neighbors for two days until her brother persuaded her to give him up, according to interviews yesterday with several persons familiar with the case.

"All of a sudden she appeared with this little baby and said it was my son," said Burnell Frizzell, Rector's boyfriend.Frizzell, who lives on D Street SE, near Fort Dupont Park, said Rector stayed with him last weekend with the baby.

"She changed him and fed him," he said. "She even sent me out to get more Pampers on Saturday."

Rector appeared in D.C. Superior Court yesterday on kidnapping charges and was released to the custody of the D.C. Bureau of Rehabilitation. A preliminary hearing was set for July 26 before Judge Joseph M.F. Ryan Jr. Rector was ordered to stay away from the baby's parents and area hospitals and to report to officials three days a week in person and two days a week by telephone.

Rector's attorney, Constance O'Bryant, said Rector is four months pregnant.

Frizzell said Rector had told him last September that she was pregnant and then appeared Friday night at his apartment with the baby. He said he did not learn until Monday that the baby was the son of Linda Jackson and Walthon Lee and had been kidnaped from George Washington University Hospital.

Frizzell said yesterday that he did think Rector had planned the kidnaping. "I think she just went up there and saw the baby and fell in love with it," he said.

According to several interviews yesterday, Rector had told some persons that she had delivered a baby but that it was kept in the hospital with yellow jaundice.

"I can't believe Sharon did this," said a friend, Theresa Williams. "She has a good head on her shoulders . . . She just seemed like herself when she brought the baby over for me to see on Friday."

Frizzell said that he and Rector had not been getting along for some time and that on Sunday he told her to go home to her mother.

Instead, Rector went half a block away to 370 Ridge Road SE, the home of Dorothy Moore, 45, a close family friend.

Mrs. Moore, who described herself as something of a second mother to Rector, said Rector told her the baby had been born a month before and had been left in a hospital because it was under weight.

But, early Monday evening, Rector told Moore the baby was the kidnaped infant, Moore said.

"Sharon said, I'm going to tell you something. That's not my baby,'" Moore said yesterday. "She told me it was that woman's baby that had been kidnaped that was on TV," and Rector started crying, Moore said.

Moore said that minutes before Rector told her of the kidnaping, Rector's brother, Donald, came to the home and took the baby away.

Norceia Williams, of 5806 Blaine St. NE, a friend of Donald Rector, said she and Donald visited Sharon Rector on Sunday. "She said she had taken the baby. She said it was the George Washington [Hospital] baby. I thought she was playing," Williams said during an interview yesterday.

The Dramatic kidnaping case began Friday night when the infant disappeared from his mother's hospital room after she received a telephone call telling her to leave the room to sign some papers. The mother, Linda Jackson, said she walked down the hall, found she was not wanted and returned to her room about five minutes later. The baby was gone.

On Monday, police and FBI officials said they received a telephone call from a woman who said she could help return the baby to his parents.

The call led to an intensive, six-hour investigation that eventually set up a rendezvous with Donald Rector and another man who had agreed to return the baby to police 9 p.m. in Fort Dupont Park.

U.S. Park Police, who were not aware of the scheduled rendezvous, intercepted the two men as they walked to the park carrying the infant. FBI and D.C. police arrived on the scene moments later and took the child to Children's Hospital, where he was reunited with his parents.