Police have arrested a Louisiana father accused of fatally punching his 7-week-old son last Wednesday, PEOPLE confirms.
According to a statement from investigators, 25-year-old Anthony Dearmas has been charged with first-degree murder and second-degree cruelty to a juvenile in the beating death of his son, Karter Smith.
Dearmas has not entered a plea to the charges against him and it was unclear Wednesday if he has retained an attorney who could comment on his behalf.
Karter was born on March 25 and has a twin brother, Karmelo.
The baby brothers had been left with Dearmas, who was watching them while their mother was at work, an official tells PEOPLE.
Karmelo was unharmed, the official says.
According to the police statement, officers were dispatched to a residence in St. Tammany Parish after receiving reports of an unresponsive infant who had stopped breathing.
“The seven-week-old was revived by emergency medical technicians and rushed to a local hospital,” the statement reads. “Doctors determined that Karter had suffered severe head injuries, which prompted investigators to question Karter’s father.”
• Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.
The statement alleges Dearmas “initially fabricated a story, but eventually told detectives that he punched Karter off of a couch, knocking him to the ground, causing him to fall on his head.”
Dearmas allegedly told police “he became frustrated due to Karter constantly crying.” He was taken into custody immediately.
In the ensuing days, Karter fought to stay alive, but doctors determined he was brain dead as a result of his injuries.
The infant died on Saturday.
An autopsy revealed that Karter sustained seven skull fractures to both sides of his head as well as internal bleeding.
“It simply wasn’t plausible, the story the father told,” the official tells PEOPLE, adding that the child had severe injuries to both sides of his head.
The manner of death was determined to be “child abuse homicide.”
“How someone can do this to a defenseless infant is beyond me,” St. Tammany Parish Sheriff Randy Smith said in the statement. “Even more disturbing is the fact this was his own child. Mr. Dearmas is where he belongs, behind bars.”