MOUNT VERNON, Ohio -- After more than a week of searching and hoping, members of a tiny central Ohio town are now grieving after the bodies of a missing mother, her 11-year-old son and a family friend were found stuffed into garbage bags and hidden in a hollow tree.

The discovery came Thursday, four days after authorities found the mother's 13-year-old daughter bound and gagged, but alive, in the basement of a home about a 15-mile drive from the wildlife area where the bodies were discovered.

Hours later, a vigil that had been planned near the family's home to support search teams became, instead, a memorial.

Knox County Sheriff David Barber said investigators were led to the bodies by an unemployed tree-trimmer accused of kidnapping the girl and keeping her for nearly four days in the basement of his home in Mount Vernon, about 40 miles northeast of Columbus.

"We were optimistic a few days ago that maybe there was a remote chance that these folks were possibly still alive," the sheriff said. "This is a homicide investigation now."

The girl, Sarah Maynard, her mother Tina Herrmann, her 11-year-old brother Kody Maynard, and family friend Stephanie Sprang were reported missing after Herrmann failed to show up for work at a local fast food restaurant on Nov. 10.

Barber said the three dead were killed in Herrmann's home in Howard, though he did not say how, and that the tree-trimmer, Matthew Hoffman, gave investigators information through his attorneys that led them to the bodies, which were removed after part of the tree was cut away.

"This is probably the saddest day in Knox County history that I can remember," Prosecutor John Thatcher said. "As elated as we were Sunday morning when Sarah was rescued, I think the tragedy today is just devastating."

Barber declined to speculate on a motive, and it was unclear how well Hoffman knew the four. The sheriff has suggested that he had been watching them.

At the Herrmann home Thursday, three purple, star-shaped helium balloons had been left in the yard and two bouquets of flowers were resting against a tree.

Hoffman, 30, has appeared in court but has not entered a plea. Knox County Public Defender Bruce Malek, who is representing Hoffman, said Thursday that he could not comment.

A day after the four went missing, a deputy found what authorities called an unusual amount of blood inside Herrmann's home, and her pickup truck was found near the campus of Kenyon College. Hoffman, whose home is about 10 miles from Herrmann's, was questioned that same day -- Barber said police found him sitting in his car near a bike trail not far from where the pickup was found.

Investigators would not discuss details of the surviving girl's ordeal but have said she is with her father and doing well, considering the circumstances.

"We're inspired by Sarah's bravery," Barber said. He said she was home at the time of the killings but added, "What she saw, I can't speak to that."