SPRING HILL — A 9-month-old infant died Friday after the boy was left in a hot car at the family home, according to the Hernando County Sheriff’s Office.Keyton O’Callaghan was found in a car seat inside the vehicle at about 11:30 a.m. by his father, who deputies said had just returned to the home at 12310 Elgin Blvd. Eric O’Callaghan, 32, took his son inside the home and performed CPR on him until rescue crews arrived.The infant was in critical condition and rushed to Oak Hill Hospital for emergency medical treatment, deputies said. He was pronounced dead there at 12:06 p.m.The Sheriff’s Office said the boy’s mother, Cami Lee Moyer, 38, had been caring for the boy since Thursday night."She was the only adult in charge of that child," sheriff’s spokeswoman Denise Moloney said.The agency did not say how long the infant was left in the car before he was discovered, or what the temperature inside was when he was found.Moloney said "detectives are still working to establish a chronological time line of events" by questioning the mother late Friday.According to a Facebook fundraiser set up in December by the mother under her maiden name Cami Rayburn, the newborn was born a month prematurely on Nov. 6. Florida Hospital Tampa doctors performed a C-section a month before his due date, the mother said, because of fluid in his belly. The infant spent a month in the Neonatal Intensive Care Unit there.The doctor was about to release the infant, the mother wrote, when the hospital discovered "liver enzyme levels were the highest that he had ever seen."The mother said her child was sent to Johns Hopkins All Children’s Hospital in St. Petersburg. Her son contracted a virus and was left in critical condition. She needed financial help to make the trip from Spring Hill and back, she said, and had her electricity turned off at one point."... It is truly Breaking My Heart to see my baby in such pain and discomfort and not be able to hold him," she wrote on Dec. 7.Both of Keyton’s parents were at the home Friday afternoon, giving statements to investigators. But the Sheriff’s Office did not allow either to speak to reporters. Neither could be reached for comment later that evening.The infant’s paternal grandfather, Richard O’Callaghan, said his son Eric was trying "to hold it together.""It’s about as bad as it gets," the grandfather said.Later that day, the sheriff’s forensics team arrived at the house at about 5:30 p.m. with search warrants to examine the home and vehicle, a light blue Chevy Cruze. TV cameras filled the shoulder of Elgin Boulevard.Lynn Creel, 66, lives three doors down. She doesn’t know the family, but spent Friday afternoon crying in front of the television in her living room after learning about Keyton’s death."I poked my head out the window this morning and saw all the cars," she said. "I had no idea it was something as terrible as this."A retired day care worker, Creel said she couldn’t understand how anyone could forget they left a child in a car long enough for them to lose their life."How do you do that?" she said. "I’m still trying to figure that one out."Times senior news researcher Caryn Baird and staff writer Justin Trombly contributed to this report. Contact Megan Reeves at [email protected] Follow @mareevs.