A 23-year-old Cheyenne mother accused of killing her 4-month-old son stood in Laramie County District Court this week and told a judge she was not guilty.
Juliette Martinez entered the plea Monday afternoon on a first-degree murder charge tied to the death of her infant son, a case investigators say began with reports of seizures and ended with doctors documenting devastating injuries throughout the baby’s body.
Martinez remains jailed on a $500,000 cash-only bond. Her boyfriend and the child’s father, 24-year-old Joseph Hanson, has also pleaded not guilty to first-degree murder.
Hanson entered his plea April 30 in Laramie County District Court. A judge later lowered his bond to $500,000 cash or surety, though he is barred from having contact with minor children as a condition if he is released.
The criminal case began Aug. 8, 2025, when staff at Cheyenne Regional Medical Center contacted police after the baby arrived with severe injuries requiring emergency transport to Children’s Hospital Colorado.
Hospital staff were reportedly concerned not only by the baby’s condition, but because they were struggling to get consent from Martinez and Hanson to life-flight the infant.
The Morning Everything Changed
According to an affidavit filed by Cheyenne Police Detective Mike Webster, Martinez told investigators she had been asleep until late that morning before noticing the baby’s breathing looked unusual. She said Hanson came into the bedroom and agreed “TH’s breathing was odd.”
The couple picked the baby up and tried to wake him before he began shaking, according to court documents.
Martinez allegedly told police she recorded a video of the infant and sent it to Hanson’s mother, who urged them to go to the hospital immediately.
Hanson gave investigators a different version of the morning. He reportedly said he had stayed awake with the baby during the night, fed him around 4 a.m., then left for work at about 7:30 a.m., leaving him in Martinez’s care.
As detectives worked to piece together the timeline, they seized both parents’ cellphones through a search warrant.
Investigators later said Martinez’s phone records conflicted with statements she had made about being asleep. According to the affidavit, her phone showed activity on TikTok and Snapchat between 8:03 and 9:29 a.m.
Police also detailed a series of internet searches allegedly made after the baby began showing signs of medical distress. Those include:
• “Shaken baby syndrome symptoms”
• “Signs father gave baby shaken baby syndrome”
• “Seizures in 5-month-old baby”
Investigators additionally reported “58 missing text messages” from Martinez’s phone during a several-hour period that morning.
The affidavit also states Hanson allegedly told a nurse that Martinez had “twin resentment.” The victim had a twin sibling, along with an 18-month-old sister.
According to investigators, the couple noticed something was wrong with the infant around 11:30 a.m. but did not take him to the hospital for roughly 45 minutes.
Holes In The Wall
As the investigation unfolded, detectives obtained a search warrant for the family’s home on Aug. 9.
Inside, investigators documented several holes in the walls “about the size of an adult fist,” according to court records. Hanson later admitted to police that he punched the holes before the couple’s other children returned home.
Detectives also found what appeared to be the shattered remains of a glass table. The frame was still sitting in the basement, while pieces of the broken glass top had been moved into the garage.
After finishing the search, investigators contacted the infant’s paternal grandmother. According to the affidavit, she told detectives Martinez typically watched the children while Hanson was at work, but there were times she was allowed to pick up only the victim — not the other children.
The grandmother reportedly told police that was because Martinez “did not have a bond” with the boy. She also said she believed Martinez had been suffering from severe postpartum depression.
‘Consistent With Child Abuse’
Medical findings outlined in the affidavit describe a long list of injuries throughout the infant’s body.
Doctors at Children’s Hospital Colorado documented severe swelling of the brain, oxygen deprivation injuries, bleeding on the brain, fractures in both legs, a spinal fracture and a possible broken rib.
Dr. Denise Abdoo, a physician on the hospital’s Child Protection Team, reportedly told investigators the injuries were “consistent with child abuse.”
Another neurosurgeon later described the infant’s condition as a “nonsurvivable diffuse hypoxic injury and severe cerebral edema,” meaning massive brain damage caused by oxygen loss and swelling.
Doctors also told police the fractures appeared recent and were not injuries the child could have silently lived with for days without symptoms.
On Sept. 2, 2025, doctors performed a test on the victim and confirmed that he was “brain dead.”
The infant was later removed from life support and died Sept. 8.
Hanson’s jury trial is currently scheduled to begin Aug. 24 in Laramie County District Court. Martinez has not yet been assigned a trial date, though court records show she has filed a demand for a speedy trial.
A scheduling conference will take place about two weeks before the trial, which is also the cut-off date for a plea agreement. If either party pleads guilty to the charges, a court will determine next steps and sentencing.
Kolby Fedore can be reached at kolby@cowboystatedaily.com.
