The bodies of 11-year-old Skyla Whitaker and 13-year-old Taylor Paschal-Placker were found Sunday by Taylor's grandfather, Peter, after he became worried when his wife tried calling the girl's cell phone and got no answer.
The Oklahoman newspaper reported police were looking at "persons of interest" in the case. Authorities are also offering a $10,000 reward for information leading to the capture of the killer or killers.
The girls, who were sleeping over at Taylor's house, decided to take a walk down the desolate road Sunday afternoon, something they were used to doing in their rural community. The Oklahoman said the girls were best friends and good students.
"I can't describe coming up on it," Peter Placker said, sobbing uncontrollably, as he tried to remember walking up on the scene, only about one-quarter mile from his house. "I done it once and I can't do it again."
Stan Florence, an inspector with the Oklahoma State Bureau of Investigation, confirmed the names of the girls. Florence said the victims were shot "multiple times" and it was unknown if they were molested.
"They were little girls, what possible motive could there be?" Sheriff Jack Choate told The Oklahoman. "You have to wonder, did they see something they were not supposed to? Were they at the wrong place at the wrong time?"
By Monday afternoon, at least 20 investigators were examining the crime scene and pursuing leads that came in overnight.
Meanwhile, relatives tried to make sense of the grisly killings in a community where some folks still leave their keys in their cars and residents who live 10 miles apart still call themselves neighbors.
Skyla was the carefree adventurer, the girl who walked barefoot almost everywhere and rode her bicycle down endless dirt roads. Where she went, her many cats followed, along with her pet goat. Skyla wanted to become a veterinarian, said her grandmother, Claudia Farrow.
To know Taylor was to love her, her grandfather said. She was the big-hearted girl who rescued helpless turtles crawling in the middle of the road and wanted to become a forensic scientist, like on the TV shows, said Peter Placker, who said he raised Taylor like she was his daughter even though he was her biological grandparent.
She was home-schooled until the family moved to Weleetka, located about 70 miles south of Tulsa.
"She was the best kid I've known," Placker said.