A woman came to 21-year-old Stephanie Ochsenbine's home in the small town of Lonedell on Friday, attacked her with a knife and left with her week-old infant, Abigale Lynn Woods, officials said.
Franklin County Sheriff Gary Toelke said authorities found a knife and other evidence near Ochsenbine's home, but would not give more details.
Ochsenbine is not a suspect, Toelke said. The attacker was described as a white woman with black hair, 5-feet-8 and 200 pounds. She was believed to be armed.
Ochsenbine helped police artists with a composite drawing of the kidnapper after leaving the hospital. The picture could be released Sunday, Toelke said.
Fliers showing the baby, called "Abby" by her family, were posted in gas stations and restaurants in neighboring Union. The 6-pound girl, born Sept. 8, has dark brown hair, dark eyes and a strawberry birthmark on her forehead.
People in the area, about 45 miles southwest of St. Louis, attended prayer services Sunday for Abby's safe return.
Search dogs, Franklin County deputies, FBI agents and several Missouri National Guard members combed the area around the home for clues over the weekend.
Callers continued to offer tips, Toelke said, but none led to a suspect.
"Any lead is good, but so far there's nothing that has stood out," he said. "There's a lot of information we have, but nothing concrete."
Ochsenbine told police she did not know the woman who came to her door Friday and entered the house after asking to use the telephone.
Ochsenbine's 1-year-old son, Connor, also was in the house but was unharmed. Ochsenbine's boyfriend and Abby's father, James Woods, was at work.
Authorities have asked hospitals and doctors to be on the lookout for anyone bringing in a newborn.
The abductor has been profiled as someone who had a child die recently or as someone who could not have children, told people she was pregnant and needed to steal a child so her lie would not be found out.
From 1983 to 2002, there were 217 reported cases of non-family infant abductions, and all but a few babies were recovered safely within 25 miles of where they had been taken, according to a 2003 study by the National Center for Missing and Exploited Children. About three-quarters of the kidnapped infants were recovered in fewer than five days.
"We're hopeful that's the case," Toelke said.