Meanwhile, investigators in a nearby county were waiting to see if one of the bodies is a suburban Kansas City mother who has been missing with her 18-month-old baby since last week.
The bodies of two adult men and one woman were found Monday on the farm west of Ottawa, which is located about 60 miles southwest of Kansas City, Sheriff Jeff Richards said at a news conference.
"We have three homicides on a very large scene," Richards said.
Richards declined to release other details, including the victims' identities or how they were killed.
Kortni McGill, of Ottawa, told The Associated Press on Tuesday that she, Corey Schlotzhauer, 26, and Shona Osladil, 21, went to the home Monday afternoon and saw in the garage a dead body covered in a tarp and weighted down with a cinder block.
"I reached down and saw teeth through the square in the cinder block. I said, 'Corey, there's a body here,'" McGill said.
McGill said she and Schlotzhauer first went to the property Sunday to check on a friend who had not been heard from since April 25. When they got there they smelled a foul odor coming from the south side of the home and called police.
McGill said sheriff's deputies went into the home and came out 10 to 15 minutes later, saying they didn't find anything and the smell was probably trash. She said the deputies then peered inside a large garage on the opposite side of the house, where there also was a strong, foul smell, but dismissed it as garbage and left.
McGill and Schlotzhauer returned to the home Monday with Osladil to feed the resident's dog and investigate the strong smells again.
Osladil said the three looked around the garage for no more than 10 minutes when they found the tarp under what appeared to be a pile of junk that had apparently been put there on purpose.
McGill said the body appeared to have decayed and that they saw a bag of baby clothes on top of the tarp. They called 911 again.
Just outside the garage entrance, McGill said, she saw a burn barrel that had baby clothes, a baby bottle and a girl's sleeping bag. She said she also saw a pair of baby's socks on the ground that appeared clean despite rainy conditions in recent days.
Olathe Police Sgt. Brad Caldwell said Tuesday that Kaylie Bailey, 21, and her daughter, Lana Bailey, were last seen Wednesday and were reported missing Friday.
McGill and Osladil - who had known Bailey her whole life - said Bailey had a relationship with a man who lived in the home and had planned to drop her baby off there Wednesday.
More than 40 detectives from various agencies were helping with the investigation. Olathe police are part of that group because of the open missing person case, Caldwell said.
Olathe police had provided the Franklin County Sheriff's Department with an address to check Friday, but Caldwell declined to say whether it was the same address where the bodies were found.
"We are waiting for confirmation that it may or may not be Kaylie, and once we know, it will determine what direction we go from there," Caldwell said, adding that the Olathe officers sent to the crime scene had returned to Johnson County.
So far, the missing baby doesn't meet the criteria for an Amber Alert, Caldwell said. He noted that when the missing person report was taken, there was no information that the child had been abducted.
"She left with her mother," he said.
Richards also acknowledged Tuesday that deputies had been to the scene Sunday and found nothing. He said when officers responded Monday, they got a search warrant and found the other bodies.
Osladil said she was upset with the way authorities handled the matter.
"I'm very frustrated," she said. "Without us going out there how long would it have been before they found that body?"