A Slidell man accused of beating his 7-week-old son to death because he was annoyed by the baby's crying has been booked on a count of first-degree murder, the St. Tammany Parish Sheriff's Office said Tuesday.

Anthony Dearmas, 25, was the only adult at home May 10 when the Sheriff's Office got a call that an infant had stopped breathing at the Eagle Lake mobile home community north of Slidell.

The child, Karter Smith, was one of a set of twins, according to his grandmother, Felicity Jenkins.

Dearmas was watching the children while their mother was at work, Jenkins said.

Initially, Dearmas told deputies that the baby had fallen off a couch. After further questioning, Dearmas said he punched his son, knocking him off the couch because he was frustrated by the child's constant crying.

But the infant's injuries weren't consistent with either story, said St. Tammany Parish Coroner Dr. Charles Preston.

The baby, whom Preston described as a "very healthy" child, had suffered seven fractures to the skull on both sides of his head, the coroner said.

Preston said the injuries could have been caused by someone squeezing or kneeling on the baby's head, or by beating the boy against something on one side of the head and then the other.

The injuries caused brain bleeds, and the child was "literally herniating out of the fracture sites," Preston said.

The baby was rushed to a hospital, and doctors were able to revive him. But he was found to be brain-dead from his injuries, and he died on Saturday.

Sheriff Randy Smith called Dearmas' explanation for his actions "a sad excuse."

"This poor child never had a chance to live, folks," he said.

The couple and their children had been living with Jenkins, the maternal grandmother.

"Everybody's thinking this boy is sane," Jenkins said. "Nobody's thinking he's going to do this."

But when Dearmas raised his voice at her daughter during an argument, Jenkins told him to leave. Her daughter had been hoping to get her own trailer at the park, but she was staying temporarily with her sister, who was out of town when the incident happened, Jenkins said.

Dearmas was initially booked on second-degree cruelty. He was rebooked Monday on first-degree murder after an autopsy determined the cause of death to be blunt force trauma to the head, and classified the death as child abuse homicide.

He remains in the St. Tammany Parish Jail.

Brandie Saba, a property manager for the trailer park, said Dearmas was not authorized to live there and neighbors did not know him.

But a resident, who declined to give his name, said that Dearmas was visibly angry when deputies arrived, walking out of the trailer with the baby in a car seat and cursing at police officers. Dearmas placed the child, still in the car seat, on the back of a vehicle before handing it to paramedics, he said.

Saba said she would never have imagined such an event happening in the Eagle Lake community. "I’m in total disbelief," she said. "I’m like, 'Y’all must have the wrong address.' "

James Sylve, a resident of the trailer park for two years, said Eagle Lake is different from other mobile home communities, and that "everybody gets along" in the neighborhood.

"It’s really shocking, terrible,” he said. "What can a 7-week-old baby do?"

Jenkins said the baby's twin brother, Karmelo, is unharmed. As for their mother, she is coping but hurting.

"She feels empty inside," Jenkins said. "She cared for those babies. She felt their first kick."

Jenkins, who recently underwent chemotherapy, said she knows now why she survived. "God left me here for this, to be my daughter's rock," she said.

The family has set up an account for help with funeral expenses at gofundme.com/baby-karter-smith.

Follow Nick Reimann on Twitter, @nicksreimann.