Man 'raped girlfriend's 4-year-old son to death and she helped him hide from cops'

A monster who allegedly raped his girlfriend's four-year-old boy to death faces the death penalty.

Keith Jordan Lambing, 20, was caught by police in Pittsburgh, in the US, a day after the tragic death of his girlfriend's son Bentley Miller.

Officers found little Bentley unconscious in the car of Kristen Herold, Lambing's mother on Tuesday morning.

He was rushed to hospital but died as a result of multiple injuries including internal bleeding, Mirror UK reports.

Prosecutors say a post-mortem exam confirmed the boy had been brutally raped.He had also suffered a number of other injuries including bruises to his neck and body.

Police issued a warrant for Lambing's arrest and found him on Wednesday evening in an abandoned house.

He has been charged with homicide, rape and multiple assaults.His mother Herold has been charged with endangering a child's life and assisting an offender.

District Attorney Richard Goldinger has said he may still charge the Bentley's mother Mackenzie Peters.Peters and Lambing also have a four-month-old child together.

The infant has been taken into protective custody.