The boyfriend of a missing Oklahoma teenager has been arrested Thursday night in connection with her death, according to the Oklahoma State Bureau of Investigation (OSBI).

Del City Police arrested Tanner Washington, 24, in the first-degree murder of 17-year-old Faith Lindsey, who was last seen on Oct. 28 and reported missing days later.

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Lindsey's sister, Justice, told Dateline earlier this month that the 17-year-old had been living with Washington in Pauls Valley and worked at a local Sonic restaurant.

“[Washington] texted me Monday night saying that he can’t find her, she’s missing, freaking out,” Justice said, according to KFOR.

After she received the worrying texts, Justice told the outlet she then got strange text messages from her sister's phone. She says the messages claimed Lindsey was with a person who wouldn't take her home and that she couldn't get a ride.

“She was misspelling a lot of things that night, and Faith [Lindsey], she has very good punctuation and spelling, and that just wasn’t her," Justice said, according to the outlet. “She kept trying to call me a lot, but hang up as soon as I answered."

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Washington allegedly told an acquaintance Faith disappeared because she had been shot at the end of October. He allegedly told police that he dropped Lindsey off at work, but she wasn't there when he returned a couple of hours later. Employees said she never showed up.

"He reported that he had received a text message that she had been shot," said Seminole County Undersheriff Matt Haley, according to KFOR. "The more we spoke with him, the more his story began to fall apart as far as what had happened."

He was charged in November with false reporting of a crime and obstruction of an officer, before authorities said they determined he played a bigger role in Lindsey's disappearance.

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The OSBI is offering a 5,000 reward for information that leads to her body. Anyone with information is asked to contact the OSBI at (800) 522-8017.