SALT LAKE CITY — A Murray woman accused of fatally shaking the 4-month-old boy she was baby-sitting in 2011 has died, leading to the cancellation of her upcoming murder trial.

Jennifer Duran Martinez, 39, died Jan. 10 "due to natural causes," court documents say. She was originally scheduled to face a jury trial in April on a first-degree murder charge in the death of Kaysen Calhoun. Before her death, Martinez was also slated for a motions and evidentiary hearing Tuesday.

An online funeral home obituary says Martinez "passed away unexpectedly at Castleview Hospital" in Price. Court documents don't give further details about her death. She had been out of police custody since posting $500,000 bond and being released from the Salt Lake County Jail in October 2011, a short time after she was charged.

Charges say Martinez killed Kaysen on Sept. 22, 2011, by shaking the baby for about five minutes after growing frustrated with him for crying. A Murray police officer testified at a preliminary hearing in 2012 that Martinez admitted to shaking Kaysen while baby-sitting him.

Police originally considered the boy's mother to be another person of interest in the case, but said they focused their investigation on Martinez after learning she was the only person with the boy in the 90 minutes or so before his death.

Martinez's defense team argued at her preliminary hearing that her confession may have been coerced during a lengthy interview with police. Her attorneys also cited a doctor's opinion that Kaysen's injuries could have been suffered several hours before Martinez was alone with him and contended that the boy's mother had expressed frustration toward her baby in text messages sent to Martinez a few days earlier.

Court records show Martinez's jury trial was scheduled seven times, but her case never reached that phase. Two of the numerous documents filed by both sides in the case were opposing memorandums about the admissability of information about the character of Kaysen's mother.

Martinez had no criminal history in Utah prior to the murder charge, court records show.

Her case was officially dismissed Jan. 19. Salt Lake County District Attorney Sim Gill didn't immediately return a message seeking more details about her cause of death. Martinez's defense attorneys could not be reached for comment.

"The state has received a certified copy of death from the Utah Department of Heath, Vital Records and Statistics to confirm the death," reads a motion to dismiss the case, filed Jan. 15 by prosecutors.


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