Police received a call from Sutter Delta Medical Center shortly before 9 p.m. Tuesday reporting that an infant was suffering from major injuries believed to be the result of child abuse, Aguinaga said.
Doctors told police that the infant was unresponsive when he was brought to the hospital by ambulance.
The baby was transferred to Children's Hospital in Oakland where he was treated for multiple fractured bones, a lacerated liver and bleeding in his brain, police said.
Doctors, however, were unable to save him and took him off life support Wednesday. Aguinaga said he is expected to be pronounced dead today.
While police were investigating the case, they learned that the boy's father, Sigifredo Lua, 23, had been taking care of the boy and his 2-year-old brother while his wife was at work. He reportedly called his wife and told her that the baby was injured and she called 911, police said.
According to police, Lua's initial statements to investigators about how the infant had been hurt were inconsistent with the boy's injuries.
Lua later allegedly confessed that he punched the baby in the face, police said.
Investigators also found evidence that the 2-year-old had been abused in the past. He has been placed into protective custody and will undergo a thorough medical exam, Aguinaga said.
Lua was arrested on suspicion of felony child abuse causing great bodily injury and booked into county jail in Martinez.
Investigators are scheduled to present the case to the district attorney's office today and will be seeking murder charges against Lua, Aguinaga said.
She said the children's mother, who was at work when the abuse happened, was extremely distraught and has been cooperating with investigators. There is no indication that she knowingly left her children in danger, police said.
Police are continuing to investigate the case and are asking anyone with information about it to call Detective Robert Green at (925) 779-6932.
