Franklin County Sheriff Jeffrey Richards said during an afternoon news conference that the prosecutor has 48 hours from the time the suspect is arrested to file formal charges. He was arrested early Thursday and is being held at the Franklin County jail on a first-degree murder charge.
Franklin County Attorney Stephen Hunting said earlier Thursday that the suspect does not have an attorney.
Richards declined Thursday morning to discuss a possible motive for the deaths, but said the investigation remains active.
"Any lead that is coming in we are going to continue to follow up on that lead," the sheriff said. "Just because we have one person in custody doesn't mean we are going to stop. I believe the victims deserve that, and I believe everyone here is going to demand that."
He said the suspect was located in Emporia, about 50 miles southwest of the Ottawa area farm where the bodies were discovered, but did not say when he was found or what led police to him.
Emporia police on Tuesday also found the car that 21-year-old Kaylie Bailey, of Olathe, and her 18-month-old daughter, Lana Bailey, were last seen in before they were reported missing last week.
Kaylie Bailey's body was found Monday at the farm west of Ottawa, where she had gone to drop her daughter off for the day with her friend, 30-year-old Andrew Stout. Friends who had gone to check on Stout found Bailey's body under a tarp in the garage and called police, who then found the bodies of Stout and 31-year-old Steven E. White, who also lived at the home on the farm.
Richards said he could not release causes of deaths because of the ongoing investigation. He said Lana Bailey is now "presumed" dead, although the child's body had not been found as of late Thursday afternoon.
"Information developed overnight indicates that Lana is presumed to be a victim of homicide," Richards said earlier Thursday. "Finding Lana is a top priority for our investigators. We will exhaust every lead and follow up every tip until we bring her home."
During the afternoon news conference, the sheriff said investigators were "ramping up" their search for the child. Law enforcement teams were scouring the area around the farm on horses and all-terrain vehicles and on foot. The FBI was searching by plane and the Kansas Highway Patrol by helicopter.
"We have to be very meticulous. We have to go fast, but not so fast we're going to miss something," Richards said.
He declined to say whether there are any other suspects, but said there are no apparent public safety concerns at this time.
The National Center for Missing and Exploited Children is assisting with the investigation as well. FBI spokeswoman Bridget Patton said the center was sending staff to Franklin County.
Kaylie Bailey's grandmother, Wilma Pettijohn, told The Associated Press on Wednesday that the family had been "kind of preparing for the last day or two" for the news that Kaylie Bailey was among the three killed at the farm. But she said the family had been holding out hope 18-month-old Lana would be found alive.
"Everything in the house reminds us of her," Pettijohn said. "It's just a lot of pain between here and OK."