A 35-year-old woman was slain yesterday in her Columbia, Md., home, while her husband was held at knifepoint, Howard County police said the husband told them.

Aruna Mittal, who ran a day care program in her home at 6453 Browsing Deer, was pronounced dead of suffocation at 2:59 a.m. at Howard County General Hospital, according to police spokesman Angus Park.

Park said her husband, Jai Mittal, 33, told police that he had been awakened by the screams of his wife shortly after 1 a.m., and that one of three unidentified intruders placed a knife at his throat when he tried to protect her. One of the attackers placed a pillow over her head, he told police.

Then, according to Mittal, the assailants ransacked the house and fled, police said.

Police said the couple's 6-year-old son and Aruna Mittal's sister, Asha Gupta, 31, who were sleeping in adjacent bedrooms, were not harmed.

Park said that police have no motives or suspects in the slaying and that the house showed no signs of forced entry.

Ila Gupta, the dead woman's sister-in-law, said the family had come to the United States from New Delhi eight years ago.

Neighbors described the cul de sac of eight single-family houses as "quiet and peaceful."