Police have also arrested the father of 3-year-old Zion Nelson and his live in girlfriend for the boy's murder.
Investigators say the toddler was beaten all over his body, by his dad, Donald Nelson and Moneesha Camp.
Officers say the suspects coached the victim's 5-year-old brother to lie to police when he was questioned. We want to warn you, details of this story are disturbing.
Since the murder, police say they have heard various versions of what happened from the suspects. But the evidence they found at the apartment, revealed the little boy was fatally beaten with a wire clothes hanger.
Fresno police say neighbors heard yelling and banging between 3:30 and 4:30 Thursday morning. A memorial now sits outside the apartment where neighbors say the couple pretty much stayed inside with two boys.
Investigators say it appears the victim, identified by his mother as Zion Nelson, was given a final beating for wetting his bed.
Fresno Police Chief Jerry Dyer said, "The boys back, buttocks, thighs, arms, chest and stomach were completely covered with injuries from marks, bruises, and cuts."
Police say around 8:30 Thursday morning, Donald Nelson called 9-1-1 to report his son was not breathing. The officer found the naked and lifeless little boy in the back seat of Nelsons car, in a neighborhood blocks from where they live. The child was wrapped only in a blanket. Officers say Nelson originally said he was homeless and they slept in the car, until police learned that was a lie.
Zion's mother says she and Donald Nelson have been involved in a child custody battle.
The victim's mother Tiara Larson said, "Now, I don't even get to see my son. I didn't get to see his last Christmas, his last birthday, nor his last Halloween. And it hurts because Donald took my kids out of spite, because I got into a new relationship, with a new person."
Larson claims she filed for custody in Sacramento County then Donald filed in Fresno County. Donald was granted custody here, even though he was arrested for domestic violence against her.
Police say Larson called last April and requested officers check on the children. At that time, the police chief says the officer who saw the children reported they appeared fine.
But neighbors, who didn't want to talk on camera, say Donald often lost control over the smallest matters. Inside the two bedroom apartment, officers found more than 60 holes in the walls. They also found blood on a bed and the wall.
Chief Dyer said, "The truth is that this incident occurred inside the apartment in the area of Saginaw and Thorne and that is where the beating took place."
Larson is now working to get custody of her 5 year old. Police say he was also abused and is in CPS custody.