A man accused of killing a 19-year-old Colorado woman claims she placed a Craigslist ad asking to be murdered.

Joseph Lopez, 22, claims he didn’t know Natalie Bollinger before the Broomfield, Colorado, teenager allegedly wrote a disturbing Craigslist post. “I want to put a hit on myself,” Bollinger allegedly wrote on her local Craiglist’s “women seeking men” section in late December, according to an affidavit first reported by Denver7. Lopez claims he answered the post posing as a hitman. Then, cops say, his make-believe profession became real.

Police found Bollinger’s body in a wooded area on a dairy farm on Dec. 29. Her boyfriend had reported her missing the previous day. The boyfriend’s Glock pistol was also missing from his home, he told police, according to the affidavit.

The teenager’s murder was a mystery from the start. An autopsy report revealed her cause of death as a single gunshot wound to the head. She had been shot from behind at close range, the bullet angling downward, as if fired from above. Although the bullet killed her, her autopsy also noted that Bollinger had “a potentially lethal level of heroin in the blood at time of death.”

The early investigation focused on a 42-year-old man Bollinger had accused of stalking her.

“He drove across country to see me.. slept behind my work for weeks,” Bollinger posted on Facebook two weeks before her death. “When I told him I didn’t want to see him anymore, he sent me hundreds of texts and calls. He parked his car in front of my house, blocking Military Highway for hours... laying on his horn.. he was arrested. Since then, I’ve asked him to leave me alone.. and he won’t. He’s sent emails for over a year close to everyday, harassing me. Making numerous account until I block him again. Threatening my family, telling me he’ll kill himself in front of me, and sending my friends and family harassing messages as well.”

But when police questioned the man after Bollinger’s death, they ruled him out as a suspect, leaving the teenager’s loved ones to wonder who would have wanted her dead. Investigators had no answers until they checked her phone, where they found 111 messages between her and Lopez on Dec. 28, the suspected day of her death.

That led police to stop Lopez on his way into his job at a local Domino’s Pizza on Thursday. Even before officers began questioning him, Lopez told them “he was sure it had to do with the girl he talked to on Craigslist,” according to the affidavit.

Lopez described himself as an unwitting executioner. While browsing Craigslist’s “women seeking men” section, the engaged 22-year-old allegedly saw an ad to the effect of “I want to put a hit on myself.” Lopez said he replied to the ad, using a hit man persona. He reached Bollinger, who allegedly told him she would pay him to kill her execution-style.

Lopez offered investigators two versions of what happened next. He initially claimed he met Bollinger, but backed out of the murder and dropped her off at her apartment, after which she shot herself.

But police collected GPS data from Lopez’s phone, placing him in the remote woods where Bollinger died. Lopez backtracked on his story. He told police he had picked up Lopez from her apartment, and tried to talk her out of the plan while they drove around looking for a suitable site of death.

Eventually, Lopez claimed, they found the wooded area. He said they prayed before he shot her in the head with a gun she provided.

On Facebook, Bollinger’s sister pushed back against Lopez’s claims.

“This man is covering up lies,” her sister wrote Saturday. “Only even worse than lying, he’s making my sister look crazy. It’s disgusting.”

The Bollinger family is not yet speaking to the media, she said, but she reiterated that she believed Lopez’s story to be a cover-up. “This was set up. This was a murder,” she wrote. “My sister did not chose this for herself or any of us.”

Lopez is being held on murder charges, without bail.