Prosecutors Mulling Death Penalty for Man Accused of Raping, Killing Girlfriend's Son, 4

Keith Lambing was hit with a slew of charges, including criminal homicide, aggravated assault, recklessly endangering another person and rape of a child.

A 20-year-old man has been arrested for the rape and murder of his girlfriend’s 4-year-old son after he was allegedly found hiding with his mother in an abandoned Pennsylvania home, authorities said.

Police responding to a call of an unconscious child found little Bentley Miller in 43-year-old Kristen Herold’s car in Butler last Tuesday, the Pittsburgh Post-Gazette reported.

The little boy was rushed to Butler Memorial Hospital, where he was pronounced dead.

Officials said Bentley died of severe blood loss due to forced sodomy, and suffered other injuries including a serious burn to his left hand that had gone untreated, as well as bruises to the head, torso and extremities that were consistent with being forcibly held from behind.

"I have never seen anything like it [in] 22 years as an attorney," District Attorney Richard Goldinger told WTAE-TV. "It’s horrific. It’s unimaginable that somebody could actually do this to any human being, let alone a 4-year-old.”

Herold reportedly told authorities she picked up the child at a Super 8 Motel on Pittsburgh Road, where her son Keith Lambing had been living for several weeks with the boy, his mother Mackenzie Peters and their shared 4-month old son.

Read: Family Friend Charged With Rape, Murder of 15-Month-Old Girl Found Dead Miles From Home

Lambing allegedly called his mother Tuesday morning, saying something was medically wrong with Bentley, who he was watching while Peters was at work, police said.

Lambing was captured by authorities after he was found hiding with his mother in an abandoned home’s attic on the day after Bentley’s death, the Post-Gazette reported.

He was hit with a slew of charges on Monday, including criminal homicide, aggravated assault, recklessly endangering another person and rape of a child, online records show.

Prosecutors said they are reportedly considering seeking the death penalty against Lambing.

“It would appear on its face, it asks for the death penalty,” Goldinger told KPHO-TV.

Herold was charged with hindering apprehension and endangering the welfare of a child.

Peters, 21, was charged with two counts of child endangerment on Thursday, nine days after the death of her son.

The serious burn Bentley had suffered prior to his death was believed to have come from an iron and was “significant enough that any reasonable caretaker would have sought medical treatment for wound care and pain management,” a criminal complaint obtained by WTAE-TV said.

Peters allegedly knew about the burn but did not seek medical treatment for her son.

Read: 2 High School Students Arrested After Allegedly Sexually Assaulting Girl At School

The complaint also reportedly indicates evidence of drugs and drug paraphernalia in the room of the Super 8 motel where Peters, Lambing, Bentley and the 4-month-old baby boy stayed.

Peter’s attorney, Joseph Keckemethy, reportedly defended his client, saying: “The idea that MacKenzie could have or should have known that anything like this would happen to her child doesn’t make any sense.”

Lambing and Peters’ infant son were taken into custody by Butler County Children, Youth and Families.

News of Bentley’s death stunned the local community, which expressed its anger about the horrific crime on social media.

"How could you not [have] called 911 at the hotel," one person wrote on Herold’s Facebook page.

"You should have been protecting that baby, not your monster son!" another person commented.

Herold and Lambing are being held in Butler County Prison.

When he appeared in court on Monday, a sobbing Lambing denied killing Bentley.

"No sir," he cried when a reporter asked if he killed the child, WTAE-TV reported.

Watch: Judge: Man Must Refrain from Sex Until Marriage for Rape of 14-Year-Old Girl