Authorities in Wyoming have charged a young couple with first-degree murder and aggravated child abuse following the tragic death of their infant son. This comes amid revelations that the mother’s phone was used to search for information on whether symptoms of shaken baby syndrome subside.

Juliette Martinez, aged 23, and Joseph Hanson, 24, were both detained after a lengthy investigation by the Cheyenne Police Department. The couple now faces serious charges and are currently held at the Laramie County Detention Center, as indicated by court documents reviewed by Law&Crime.

The investigation began on August 8, 2025, when staff at Cheyenne Regional Medical Center alerted authorities about a 4-month-old baby, referred to as TH in the documents, who was brought in by his parents. Upon examination, doctors determined the child required urgent medical attention and needed to be airlifted to Denver Children’s Hospital. However, hospital staff struggled to reach the parents during this critical time.

A Cheyenne police officer, responding to the situation, visited the family’s residence on Miami Circle to facilitate communication between the parents and medical personnel. Once in Denver, further medical evaluations revealed the infant had suffered severe injuries, including fractures and life-threatening brain trauma, suggestive of physical abuse.

Unfortunately, despite the medical efforts, the child’s condition did not improve. He was placed on life support and, tragically, passed away on September 8, 2025, after being removed from life support.

As part of the investigation, disturbing details emerged, including an affidavit of probable cause obtained by Cowboy State Daily. It revealed that Hanson allegedly informed a nurse about Martinez’s struggles with “twin resentment,” noting that the infant had a twin sibling and an 18-month-old sister.

Officers interviewed both parents. Martinez reportedly said that before TH’s initial hospital visit, she and Hanson “both agreed TH’s ‘breathing was off.’” When they picked him up, they noticed the boy was shaking.

They are said to have brought him to the hospital about 45 minutes later.

Martinez allegedly revealed more in her discussions with officers. She said that on that same day of the initial hospital visit — Aug. 8, 2025 — she slept until about 11:20 a.m. When she woke up and noticed TH’s breathing, she said she recorded a video and sent it to Hanson’s mother, who told them to take him to the hospital.

Hanson said he was awake the previous night with TH in the living room, per the affidavit. He recounted that he left the house at about 7:30 a.m. to go to work and left the child in Martinez’s care.

Investigators also searched both parents’ cellphones. When they did so, they apparently had questions concerning Martinez’s story.

For example, though she claimed she was asleep at the time, the search found that her phone was active on Snapchat and TikTok between 8:03 and 9:29 that morning, according to the local newspaper. Her phone also had “58 missing text messages between 6:42 a.m. and 11:45 [a.m.],” the affidavit stated.

Her phone’s internet search history also allegedly showed several searches having been made after the parents said they saw their son shaking, including: “Shaken baby syndrome symptoms,” “Shaken baby syndromes symptoms go away,” “Signs father gave baby shaken baby syndrome,” and “Seizures in 5 month old baby longer than 5 minutes.”

Detectives received the completed autopsy for TH on March 20, Cheyenne police said, noting the chief coroner involved “determined the cause and manner of death to be homicide.” The parents were arrested on April 8, 2026.

Martinez and Hanson appeared in court on Thursday and are set to return on April 17.