A couple from suburban Philadelphia has been charged with the murder of four-year-old Tahjir Smith.

19-year-old Lisa Smith, the boy’s mother and her 26-year-old boyfriend, Keiff King, were arraigned on Friday (April 6) and each was charged with first degree murder. They’ve been held since January.

Investigators say Smith and King told them they used their hands and a sandal to give Tahjir a “butt whooping” for spilling cereal he was eating on January 22. That was after an autopsy showed that the young boy died as the result of a violent, sustained beating.

According to CBS affiliate Philly 3, after searching the couple’s home, law enforcement described the place as “deplorable” with Montgomery County District Attorney Kevin Steele adding that “there were insects and roaches in the house.”

Initially, Smith, who is currently pregnant, told investigators that Tahjir suffered from an unknown medical condition, which left his legs “wobbly” and him short of breath upon the couple returning home from the mall the day he died. A subsequent medical examination proved otherwise.

“[They struck] his body so hard there were pattern imprints on the boy's buttocks when the police were finally called,” Steele said.

Police are also claiming that the Tahjir suffered broken ribs and burn marks after his mother threw him in the shower under scalding hot water.

Since Lisa Smith and Keiff King have been charged with first-degree murder, Pennsylvania law makes them not eligible for bail. Neither’s lawyer has commented on the charges.