OMAHA, Neb. — Police, neighbors and friends struggled Tuesday to unravel the mysterious deaths of a Nebraska woman and her 10-year-old son that began with them appearing to go on an excursion and ended with their bodies found deep in the woods of an Iowa state park.

Charlotte Schilling, 41, of Plattsmouth, Neb., and her son, Owen, had been missing since May 10, when the mother checked the boy out of his elementary school. It wasn't unusual for Schilling to surprise her children with short road trips to parks, zoos and other nearby attractions, relatives said.

But the woman always called home and the excursions never lasted long. Her family grew worried when neither she nor Owen returned home, and Schilling's cellphone went unanswered.

"None of this makes sense," said Polly Best, who lives next door to the Schillings. "It's just tragic. There was never a hint of anything wrong there."

Best stood outside the family's home Tuesday holding a roast she had cooked for relatives gathered inside. Yellow police tape blocked the Schillings' driveway and front steps from reporters trying to talk to family members and neighbors wanting to offer condolences.

Surveillance video from a convenience store in the area where the woman and boy's bodies were found Sunday showed Owen hugging his mom and Schilling kissing her son on the head. KETV in Omaha aired the store video footage.

"I just can't believe it," Best said. "That did not look to me like a woman who would hurt her child."

But that appears to be what investigators believe may have happened.

Police in Council Bluffs, Iowa, said Tuesday they "do not suspect any outside foul play" in the deaths of Schilling and her son. Their bodies were found Sunday evening in Lake Manawa State Park, south of Council Bluffs in western Iowa, about 20 miles north of Plattsmouth.

Investigators stopped short of labeling the case a murder-suicide, saying they must wait for further autopsy results before determining the cause of death.

Council Bluffs Sgt. Dave Dawson said he expected to announce the cause of death by the end of the week. Investigators are leaning toward the belief that the bodies had been in the spot where they were found since May 10, the day that Schilling checked Owen out of Wade Robin Elementary School in Bellevue, Neb., and they went missing.

The day after they disappeared, police found Schilling's vehicle at the same park where the pair would eventually be found dead. Schilling's cellphone and wallet were in her car.

Nine days after the discovery of the vehicle, a passer-by found the woman and boy's bodies in thick woods about a half-mile from where the car had been parked. Authorities had to rely on autopsy results to confirm the identities because the bodies had decomposed.

"I just about went to my knees," said the family's neighbor, Naomi Raposo, 50, describing her reaction to news of the deaths. She just found out Tuesday, not realizing that earlier reports of bodies being found were about Schilling and her son.

"They've been very peaceful neighbors. They're very friendly," Raposo said.

The night before the woman and boy went missing, another neighbor, Athena Meneses, said she spoke to Schilling at a local Cub Scout meeting, where Meneses had taken her own son and Owen. Owen had wanted to join the group, Meneses said.

"I didn't really know her very well, but she seemed upset. She had a bump on her head," Meneses said of Schilling. "She didn't seem like she was really happy that night. She said she wasn't feeling well and that she'd like to go home. She told me that she had fallen down earlier that day."

Meneses and her family moved to Plattsmouth about two years ago, just blocks from the Schillings. She said Owen was a playmate to her four oldest children, ages 6 to 14.

"We had a trampoline, and he would come over almost every day to play on that," she said.

Owen was closest to her 8-year-old son, Christian.

"I think my son said it best: He was energy-filled, and a very happy little boy," Meneses said.

School officials said students were having difficulty coping with the fifth-grader's death. Tuesday was the last day of school before summer break.

"There's a lot of sadness and a lot of confusion," said Bellevue Public Schools Superintendent Frank Harwood.

Cody Johnson, a clerk at the Lake Manawa convenience store where surveillance video captured Schilling and her son shortly after she checked him out of school, was one of the last people to see them alive.

Schilling bought a pack of cigarettes for herself, and apple juice and snacks for Owen.

"The kid came in all hyper, like a normal kid would be, and went around looking at stuff," Johnson said. "Nothing seemed out of the ordinary. They were just like any other mom and son. There was nothing that showed me anything bad was going to happen."