A Pennsylvania mother and her boyfriend are facing murder charges in the beating death of the woman’s young son.

Prosecutors say Lisa Smith, 19, and Keiff King, 26, beat Smith’s 4-year-old son, Tahjir Smith, to death after he spilled his cereal on the morning of Jan. 22.

“This was a violent sustained beating of a 4-year-old that caused his death,” Montgomery County District Attorney Kevin Steele told KYW.

According to a forensic pathologist, Tahjir died of multiple blunt-force and thermal injuries and shock. Smith and King allegedly forced the boy to hold a push-up position for an extended period of time and beat him repeatedly with a sandal when he couldn’t hold it.

“Striking his body so hard there were pattern imprints on the boy’s buttocks when the police were finally called,” Steele said.

Officials say King also admitted to forcing Tahjir into a scalding shower, which left a burn on the boy’s shoulder.

 According to KYW, the autopsy also showed several old rib fractures, leading investigators to believe this wasn’t the first time Tahjir had been beat.

Neighbors are shocked over the horrors that unfolded in Smith’s house. Charlie Evans said he’s lived in the neighborhood for more than five decades and never knew anything was happening.

“After all these months, it is still shock and disbelief that this little boy would have to go through that torture and none of us could see or understand it was evening happening,” Evans said.

Smith and King are both charged with first-degree murder.