Victim’s name: Rosa Joan Arguello, 30
Where body found: in a ditch along the 12900 block of Quebec Street
Investigative agency: Thornton Police Department
Date killed: Oct. 17, 2003
Cause of Death: Stabbed 12 times
Person of Interest: James Joseph Armijo
Rosa Joan Arguello struggled to speak after she was stricken by meningitis as a young child.
Rosa Arguello, 30, courtesy Thornton Police Department
“She was 5 before anyone ever understood what she was saying,” her mother Arizona Humeyumptewa-Winters said.
She had difficulty likewise learning to read and to do math in school. Her challenges spilled over into her adult life, Humeyumptewa-Winters said.
Arguello was only able to find minimum-wage jobs and often lived on the street.
She was very trusting; too trusting of the wrong types of people, Humeyumptewa-Winters said. She often bounced from homes of one undesirable acquaintance to the next.
“She was very gullible. She befriended people she shouldn’t have. She didn’t live the best life,” her mother said. “I was always worried about her out there on the street. I didn’t know how to reach her.”
Whenever Arguello had a child – she had three – the child was given up for adoption, twice with extended family. She had two boys and a girl.
But what Arguello’s mother loved most about her was that she had a golden heart. As a child she often mopped the kitchen floor for an elderly woman who lived up the street or ran errands for her. Even though she didn’t get paid, she loved being with her. She had a great respect for the elderly, she said.
Arguello also loved children and sometimes got work baby-sitting. She wouldn’t just watch the kids. She liked to do fun activities with them like painting designs with fingernail polish on pine cones.
She had a distinctive laugh and she was always laughing.
“She had a laugh that made other people laugh,” Humeyumptewa-Winters said. “She was so sweet. She was my baby.”
Humeyumptewa-Winters sometimes helped her daughter get jobs. Arguello cleaned houses, she said.
Arguello had a succession of bad relationships with men, her mother said.
One particularly bad connection was with the father of one of her sons, James Joseph Armijo.
“I don’t think he treated her very well,” she said.
Two weeks before Arguello went missing, she visited her mother’s house.
“She was lying on my bed and I was stroking her hair,” Humeyumptewa-Winters said. “I was telling her she could do better than she was. She could go back to school. I told her she was smart and could do anything she wanted to. She talked about starting her own cleaning service.”
It wouldn’t be.
Arguello’s body was found Oct. 17, 2003 in a ditch along the 12900 block of Quebec Street. She had been stabbed 12 times including in the heart.
In doing so, the killer permanently injured her mother’s heart as well.
“I can’t believe anybody could do that,” Humeyumptewa-Winters said. “I believe some people are walking, breathing dead people with no soul.”
Thornton police interviewed Armijo, along with several other “persons of interest,” but no arrest was made, said Thornton Det. Shawn O’Keefe. He denied having anything to do with her death.
James Joseph Armijo, courtesy Colorado Department of Corrections
Armijo’s name came up again a year later, though.
On Sept. 22, 2004, his 44-year-old former girlfriend Jacklyn Oetker’s body was found decomposing in a Chevrolet Blazer at the southwest corner of a parking lot at West 100th Avenue and Wadsworth Parkway.
She had been stabbed 30 times and had been left in the car several days. Westminster detectives found her after relatives reported her missing.
On Sept. 16, 2004, the night Oetker failed to make it home, Westminster police had contact with Armijo at a King Soopers store in the same shopping center where Oetker’s body was found.
Armijo had called police to the grocery store and claimed he was an FBI agent and that three men were after him, according to a Denver Post article.
The police officer who responded thought Armijo was “delusional.” Armijo was last seen walking across the parking lot toward the area where Oetker’s body was later found.
Armijo, a convicted felon who had molested a child in New Mexico, was 33 at the time. He was charged and convicted of killing Oetker and sentenced to life in prison.
Though police tried to find a connection to Arguello’s similar knifing death, it has yet to be found. But Armijo has not been excluded as a possible suspect either.
O’Keefe has travelled to New Mexico, Nebraska, Kansas and Illinois tracking down leads in the case over the years.
“We’ve been quite active on it,” he said.
Armijo remains a person of interest in Arguello’s stabbing but there are others who have also been investigated.
O’Keefe recently sent evidence to the Colorado Bureau of Investigation’s crime laboratory for testing. He is awaiting the results.
“We’re hoping new technology will help identify the killer,” he said.
Arguello’s death has always puzzled O’Keefe.
“I don’t know why anyone would have a motive to kill her,” he said.
O’Keefe hopes someone will come forward and divulge what they know about the case.
“I can’t tell you how grateful I am that he has not given up,” Humeyumptewa-Winters said of O’Keefe’s pursuit of his daughter’s killer. “He is just tireless.”
She said it’s been impossible to recover from her daughter’s murder.
“I’ll be in a store and hear a laugh that reminds me of her,” Humeyumptewa-Winters said. “Sometimes you dream and she’s there and then you wake and you realize she’s not there and it’s not real. It never goes away.”
Contact information: Det. Shawn O’Keefe can be reached at 720-977-5043. Denver Post reporter Kirk Mitchell at 303-954-1206 or kmitchell@denverpost.com
