The teenager called 911 and said that his mother had been kidnapped; police believe he killed her

Arizona authorities have charged an 18-year-old with killing his mother after police say he called 911 to report she had been kidnapped minutes after a jogger found her dead.

The Pinal County Sheriff’s Office said on social media that officers received a call around 9 a.m. on Wednesday, Oct. 30, from a jogger who “discovered a body in a farmer’s field” in San Tan Valley and reported it to police.

Investigators said they identified the body as that of 38-year-old Mary Collier and said in their release that she “appears to have been the victim of a homicide.”

According to police, “less than ten minutes” after they received a call from a jogger about searching for a deceased woman, her teenage son called 911 “about a kidnapping” at their home. Officers say they have confirmed both calls involved the same woman.

Deputies found the son, who has not been publicly named, “suffering from self-inflicted wounds” after they arrived at his home and he “was taken to the hospital.” Police said he has been “identified as a murder suspect” and upon his release from the hospital, he will be booked into the Pinal County Jail on a charge of first-degree murder.

Police have not released a possible motive for the killing, but they believe it may have stemmed from a possible argument that occurred Tuesday night and continued into the next day, according to reports from KTVK-TV and Fox 10 Phoenix.

The jogger who found Collier’s body, James Ritchie, told KTVK-TV that he initially thought the body “looked like a Halloween scarecrow or something” as he walked by. However, as he got “closer and closer, he began to look like a real person” and he found a “blade” near her body.

“Instantly, when I saw the blood on the blade, I thought: no, this is a corpse. This is a crime scene,” Ritchie told the publication. “The handle was broken in two and the blade was like just laying there and there was blood all over the blade.”

Want to stay up to date with the latest crime news? Sign up for PEOPLE’s free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.

Collier’s niece Rebecca Hatch remembered the victim as an “incredible person” in an interview with Fox 10 Phoenix, adding that she “was so passionate about her faith” and was also “selfless.”

“I’m sure if I could hear her last word, it would be about her family, about the people she loved,” Hatch said. “That’s the kind of person she was.”

Hatch also noted that it was “completely incomprehensible” that her son was accused of committing a crime, adding: “Of all the people in the family, Mary was the one he loved the most; she was the one he respected most. inexplicable.”

According to a GoFundMe set up for her family, Collier is survived by her husband and four children, the youngest of whom is 10 years old.

The Pinal County Sheriff’s Office said the incident remains under investigation.