This week, he was found guilty of that charge, as well as first-degree murder, in relation to the crime -- an especially horrific one as indicated by the information released by the Jefferson County District Attorney's Office.
Imagine the toll it took on a jury over the course of a two-week trial focusing on details like these.
According to the DA's office, police and emergency personnel arrived at a Quay Street address in Lakewood to find nine-week-old Lilian Leyba not breathing and cold to the touch -- and no wonder, since her skull was crushed. One paramedic described the back of her head as feeling like "mush."
The day had begun as a family gathering, with relatives congregating at the Quay Street address owned by Leyba's grandparents; Leyba, Lilian and Jennifer Chavez, the child's mother, lived in the basement. But by the evening, the get-together reportedly deteriorated into yelling and fighting presumably fueled by alcohol consumed during the day. When Leyba was arrested, his blood-alcohol content registered .26, three times over the legal limit.
Along the way, Leyba is said to have physically attacked his mother while holding the baby. He then handed the child off to his twelve-year-old stepsister, but subsequently took her with him to the basement while still "angry and drunk," the DA's office account says.
Family members were reportedly worried that Leyba was too drunk to take care of the baby, and their concerns proved well founded. When they checked on them ten-to-fifteen minutes later, Leyba was unconscious on his bed with the lifeless baby beside him.
Her injuries were startling. Doctors testified at trial that she had three major skull fractures, including one from ear to ear, almost seven inches long, as well as bruises behind her ear and at the back of her neck. These experts likened the injuries to ones associated with a ten-story drop or a serious car accident during which the child was ejected from the vehicle.
Despite this evidence, Leyba's family "erupted into angry shouts and threats aimed at the judge, the jury and others in the courtroom" when the guilty sentences were announced, the DA's office narrative notes. The jury had to be escorted from the courtroom for their own safety.
As for Leyba, who has a previous child cruelty bust on his record, he'll be sentenced on December 17. A possible sentence: Life in prison without the possibility of parole. Here's a larger version of his booking photo:More from our Colorado Crimes archive: "Colorado's top 100 most wanted sex offenders: A mug shot gallery."