A 17-year-old girl who has been missing since May 9 was killed by a 20-year-old acquaintance, according to police who charged the man with murder after finding a body in his yard.

Phillip Kyle Blankenship was arrested Friday on a murder charge and held pending a court appearance today.

Burke County authorities think the body found behind Blankenship's home late Friday was that of Olivia Nichole Seals of Morganton.

Sheriff John McDevitt said the body matches a description of Seals, and an autopsy will be performed to confirm the identification and determine the cause of death.

McDevitt said authorities went to Blankenship's house after he took a lie detector test, and found items inside that were consistent with a struggle -- including bloodstains. The body was found when the search moved outside.

"I'm not at liberty to say what was located inside his home, so our case will not be compromised," McDevitt said. "But it was quite obvious that an act of violence had occurred."

Olivia Seals was reported missing 11 days ago by her father, Hugh "Nick" Seals.

He told authorities that Blankenship later claimed he dropped off the girl on a dirt road in front of her home at 2 a.m. May 8, and that he gave Seals his daughter's purse and cell phone, saying she left the items in his truck.

But McDevitt said investigators think that, shortly after Olivia Seals went missing, Blankenship tried to persuade her father that she was in the Asheville area by sending him text messages.

Nick Seals told police that the messages were not worded or sent in the usual way his daughter communicated.