Medford - A mother and her four young children who were pulled from a burning house on Monday had stab wounds and died, and the father was under police watch.

Authorities said medics initially treated the victims on the lawn of the small house for smoke inhalation, but it later became clear the victims had also been stabbed. They were all pronounced dead after being taken to a local hospital. Autopsies are pending, and police were searching for the weapon used to stab the victims.

The 51-year-old father, who was also taken to the hospital, was not immediately charged, said Police Chief Tim George.

"He is not free to leave, let's put it that way," George said, adding that he did not think neighbors had anything to fear from a killer at large.

George characterized the fire as arson and the deaths of the 30-year-old woman, her sons aged 7, 6, and 5, and her 2-year-old daughter as homicides.

"We do know there was out of the five deceased, a combination of stab wounds and smoke inhalation in all of them," he said.

Their names were withheld until family members were notified.

A man at the house called in a missing person report for the mother earlier in the morning. Police said she returned unharmed after being located a few blocks away.

Around 9 a.m., someone asked neighbor Calvin Kennedy if he had seen smoke coming from the house. Kennedy said he went to the house and pounded on the door, but got no response.

Kennedy said he told the other neighbor to call police and flagged down officers, who also knocked at the door.

"By then smoke was starting to come up under the eaves," Kennedy said.

Kennedy said the family had moved in less than a year ago, and seemed nice. The mother occasionally took the children out for walks.

"Never saw any trouble," Kennedy said. "It's just sad."