Along with first-degree murder, Charlton was charged with the theft of Lyne's car and faces anywhere from 21 to 28 years in prison if convicted.
"The tragic murder of Ingrid Lyne has left a family and community in a spiral of grief and anguish," King County Prosecuting Attorney Dan Satterberg said in a statement obtained by PEOPLE. "We may never understand why she was killed, but the police and prosecutors working on this case have done a tremendous job of piecing together a solid case against the person we believe to be responsible for her death."
According to probable cause documents obtained by PEOPLE, Charlton, 37, was arrested on Monday and told police in an interview that he had been dating Lyne for about a month, following their introduction on a dating site. On Friday, the mother of three picked him up in Seattle and the pair went to a Mariners game, after which they headed to a bar where Charlton's sister works.
Following their outing, Lyne and Charlton returned to her home in Renton, where he "thinks" they had sex, but he claimed to not remember much of the evening. According to what Charlton told police, he "thinks" Lyne drove him back to Seattle where he slept on a sidewalk. He also told police he's "not a normal person," as he is homeless and suffers from a drinking problem.
Montana DOC Photo
Described as "rather nonchalant," during his conversation with police, Charlton also revealed that he spent Saturday and Sunday night at his ex-girlfriend's home in Lake Stevens, Washington – a city about 48 miles north of Lyne's home in Renton and 36 miles north of Seattle.
Charlton's ex-girlfriend later confirmed to police that he did spend Saturday and Sunday at her home (claiming he usually sleeps at a shelter), although he was supposed to arrive Saturday morning but did not show up until 10:30 p.m., because "something had come up."
According to the documents, she also alleged to police that Charlton is a "mean drunk," but has never assaulted her. Upon his arriving at her home, the ex-girlfriend also noticed that Charlton had a swollen and injured lip, but he told her he had been robbed in the city.
When interviewing him, officers also noted abrasions on the suspect's lips and face, as well as small scratches on his chest.
On Sunday, the ex received a text from Charlton's sister, saying that officers wanted to talk to him. When she questioned him about it, Charlton told her it had to do with a woman he was dating that had disappeared.
Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.
Lyne's disappearance garnered national attention on Monday when it was revealed that police were investigating the missing woman in connection with body parts found in a recycling bin in a residential area of Seattle.
During a press conference on Monday evening, Seattle Police Chief Kathleen O'Toole revealed that, despite not yet having confirmation from the medical examiner's office, officers believed that the body parts – a head, a left arm, and a right leg – belonged to the missing nurse.
"The head showed no signs of decomposition and the facial features were intact and distinctive," court documents obtained by PEOPLE read. "An examination of Lyne's driver's license photograph convinced investigators that the victim at the Medical Examiner's office was Lyne."
Seattle police later obtained a search warrant for the nurse's home, in which they found a 15-inch wood saw, and bags that were "identical in color and size" to those that the body parts were found in. An initial test for blood in the bathtub came back negative, however once CSI returned to the home and "removed the plumbing beneath the bathtub … they found blood and flesh."
Charlton – who has an extensive criminal history with offenses in Washington, Florida, Utah, Idaho, California and Montana – is currently being held on $2 million bail and is expected in court on April 27 for his arraignment.
Reporting by HARRIET SOKMENSUER