At least 30 D.C. police detectives and FBI agents are working full time on the investigation of the kidnaping of a new-born boy Friday night from his mother's room in George Washington University Hospital, D.C. police said yesterday.

Authorities interviewed several relatives and friends of the parents of the missing baby yesterday. They also interviewed hospital staff members and a woman who was involved in the 1971 kidnapping of a 2-month-old baby. However, officials said they have no suspects.

Linda Jackson, the 24-year-old mother of the missing baby, was resting yesterday at her mother's Southeast Washington home. The baby's father, Walton C. Lee, also was at the home.

Throughout the day and night, friends and relatives came to comfort the couple. At one point last night, Jackson began weeping uncontrollably over the loss of her baby. Her sister and a friend placed their arms around her to console her.

"They're trying to keep my mind off of it," Jackson said later. "All I've been seeing is my baby's face. It's like a picture that will never go away."

"I'm hoping that God will open their (the kidnaper's or kidnapers') hearts and send the baby back safely," Jackson's mother said.

She said her daughter has been "sleeping some, but she dosen't have an appetite. She's under a lot of worry and strain."

Family members expressed shock and bewilderment at the disappearance of the baby, which is the 15th grandchild in the family of seven girls and two boys.

"At first, I thought how could this happen at a hospital," said Jackson's mother. "It's so unexpected. . . . We just want the baby back."

Jackson said she came home from the hospital Saturday even though hospital officials wanted her to stay longer. "I told them I felt if I came home from the hospital to be around my family, I would feel better than staying in that room."

The baby, born early Thursday morning, was kidnaped about 8:15 p.m. Friday when Jackson left her third-floor room briefly in response to a telephone call.

Jackson said a woman caller told her to go to the obstetrics area, about a minute's walk from her room, to sign some papers.

When she got there, she was told that there were no papers for her to sign, she said. When she returned to the room the baby was gone.

Jackson and the baby, who was to be named after his father, were the only occupants of the semiprivate room.

Hospital officials declined yesterday to discuss security procedures. However, visitors to the third-floor maternity ward yesterday were required to identify themselves and were given name tags to wear while on the floor.

Police issued a plea yesterday to the kidnaper to take the baby to a physician because of the possible medical risk involved.

Dr. Maureen Edwards, a pediatrician at George Washington University Hospital, said that when the baby was taken he weihged 5 1/2 pounds, which is small for a full-term baby. She said the baby should be fed an infant's formula of two to four ounces every four hours.

The baby, who was circumcised shortly after birth, was wearing an umbilical clamp when he was taken. The clamp is about 2 inches long and made of cream-colored plastic and resembles a barrette. The clamp normally is removed from the umbilical cord with a special medical device and should not be pulled off, Edwards said.

Edwards also said the baby could develop jaundice if he is not fed properly and kept warm.

The baby was wearing a white tee shirt and paper diapers and was wrapped in a white blanket when he was taken.

Authories said that anyone with any information should call the robbery squad at 727-4400 or the Fbi's Washington field office at 252-7801.

In the 1971 kidnaping, a two-month-old boy was taken from Freemen's Hospital, predecessor of Howard University Hospital, by a woman who claimed to be a welfare worker.

After an 11-day search, police recovered the boy through the assistance of a tip from a citizen. An unemployed hotel maid was arrested in connection with the kidnaping.