The deal seemed too good to be true: Truck for sale. $200. No longer needed by owner.

A Florida woman had advertised the bargain last week at the unbelievably low price to a buyer willing to take it off her hands as soon as possible.

Why was she in such a hurry to sell the truck dirt cheap? The owners had been killed.

“She actually was telling people that the victim was shot in the head, and was dead, and that they needed to get rid of his truck,” Polk County Sheriff Grady Judd said at a news conference Saturday, recounting the conversation between buyer and seller.

That is what 19-year-old Amberlyn Nichols told a prospective buyer who reported the crime, according to the sheriff. The allegation was news to police, who did not know the truck’s owner and his wife were missing before they learned about the suspicious car deal.

Deputies arrested three people in the killings Saturday, including Nichols, her boyfriend and her stepfather.

On Friday, sheriff’s deputies drove to the house of the truck’s owner, Raymond Mark Cline, 33, and his wife, Crystal Ann Cline, 37. Raymond was last seen Feb. 21 while scrapping metal. Neither had been heard from since. They weren’t home when deputies pulled into the dirt driveway, south of Haines City, Fla., on the northern edge of a wooded swamp.

But inside the house, police found Nichols, who confessed her role in a grisly double-homicide, Judd said.

Nichols told deputies that the Clines owed her stepfather, Todd Michael Jackson, a lot of money, about $30,000. About two weeks before deputies showed up Friday, the 34-year-old Jackson sneaked into the Clines’ home while they slept, according to the confession Nichols gave to Polk County deputies. Jackson, apparently angry over the unpaid debt, quietly slipped into their bedroom, then shot the couple, authorities allege.

“Not only were they in bed asleep, but I’m certain they might have been having wonderful dreams,” Judd said, recounting investigators’ leading theory about the killings, based on witness statements and Nichols’s confession. “Todd Jackson is the one who fired the fatal shots into the body of [Raymond] Mark and Crystal while they were sound asleep in their home.”

Jackson then allegedly called Nichols and her 19-year-old boyfriend, Larry “L.J.” Waters Jr., to help clean up the crime scene.

Waters and Jackson removed an air conditioner unit before lifting each of the bodies and pushing them through the bedroom window, Judd said. Using a furniture dolly to carry the bodies, the men allegedly carted the Clines’ corpses into the swamp behind their home.

Meanwhile, Nichols, who usually lived in a tent about 20 miles west in Saddle Creek Park, started staying in the Clines’s home every few nights. That’s where deputies found her Friday. Judd said Nichols admitted to trying to hawk the Clineses’ truck, and walked deputies into the swamp to show them where the bodies were buried. By the time deputies found them Saturday, the bodies had decomposed significantly, the Polk County Sheriff’s Office said.

“Keep in mind the bizarreness of this,” Judd said Saturday. “Why in the world would one of the accessories be trying to sell the truck for $200 and tell the people she’s trying to sell it to the reason the victims don’t need it is, they were murdered? Just crazy.”

The sheriff credited the quick-thinking buyer who reported the fishy truck sale — and the story of its slain owner — to the sheriff’s office.

“Some of our witnesses were extraordinarily helpful,” Judd said. “They went above and beyond, but that’s what good people do in Polk County. They right wrongs, and our witnesses were trying to right a wrong.”

Deputies arrested Jackson on Saturday evening. They charged him with two counts of first-degree murder. Nichols and Waters were charged with accessory after the fact and failing to report a death. Nichols also faces a charge for dealing stolen property. Nichols and Waters had their first court appearances Sunday, the sheriff’s office said. Jackson’s first appearance is scheduled for Monday.