A man arrested in the shooting death of a 19-year-old Broomfield woman told police he shot her after responding to an ad she’d placed on Craigslist looking for someone to kill her, according to court documents obtained by 9Wants to Know.

Joseph Lopez, 22, told investigators he met Natalie Bollinger in late December after responding to her advertisement and eventually agreed to shoot her, apparently in exchange for being allowed to keep her gun as payment, according to an arrest affidavit.

He is scheduled to be in court Wednesday for the formal filing of charges.

According to Lopez’s arrest affidavit obtained by 9Wants to Know, Lopez told police he met Bollinger after responding to her add on Craigslist.

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Lopez, who is engaged to another woman, told investigators, he was browsing through “Women seeking men” section, when he saw what he described to investigators as an “unusual post” titled something to the effect of “I want to put a hit on myself.”

Lopez told Adams County Sheriff’s Office investigators, he texted with Bollinger and eventually met her on December 28.

According to court records, Lopez told investigators he agreed to meet with Bollinger to kill or assist her in suicide. But said his goal was to convince the young woman not to go through with her plan.

He told investigators he had struggled with depression and suicide in the past, telling them when he was a senior at Adams City High School, a teacher found his journal full of stories about kidnapping, torture and execution. According to court records, Lopez said he had to talk to the school counselor about it.

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Lopez’s arrest affidavit said he picked her up, drove around and discussed how she “wanted to be shot and killed.”

Bollinger told Lopez, according to court documents, she “wanted it to happen quickly.”

Joseph Lopez also said that Natalie Bollinger told him that she wanted to get on her knees and be executed from behind because she did not want to see the gun,” the affidavit said.

Lopez told investigators Bollinger provided the gun for him to use and told him she could keep it if he wanted to.

Bollinger’s boyfriend reported her missing on December 28, 2017, according to the court documents, and reported his Glock 9mm pistol was missing. The next day, December 29, a woman’s body was discovered in unincorporated Adams county. The body was later identified as Bollinger.

Court records show Lopez changed his story, first telling investigators Bollinger shot herself in the temple, then when confronted with evidence, Lopez told detectives Bollinger “convinced him to help kill herself.”

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Lopez said, “they parked the car and walked over to the trees,” where the two knelt-down beside each other.

Lopez told investigators he and Bollinger, “said a prayer together and then he held the gun with both of his hands.”

He then shot Bollinger, panicked, grabbed her purse off the ground and the gun and drove to his house, according to the arrest affidavit.

According to court documents, investigators found Lopez by checking Bollinger’s phone and tracking down her text messages; approximately 111 texts were sent and received on her phone from an unknown number. That number was later tracked down to Lopez.

During the investigation friends and family members told detectives Bollinger had a past history of suicidal thoughts. But her grandmother told authorities Bollinger was happy and was looking forward to her “recent acceptance to school.” The investigation determined Bollinger also applied for numerous jobs and the day she disappeared one of those companies call her back.

The Adams County coroner said Bollinger was killed by someone shooting her in the head. The coroner also determined “there was a potentially lethal level of heroin” in her blood at the time of death.

9NEWS reached Bollinger’s grandmother Mary Bollinger on the phone. Bollinger declined to be interviewed, but said Natalie was a “smart girl.”

“There is no way she did this. She lived with me,” Bollinger said and hung up.

9Wants to Know found Facebook pages for people who identify themselves as the victim’s mother, father and sister, reached out to all of them, but have not heard back.

9NEWS called what according to court records could be the suspect’s mother and she said she couldn’t comment.