James Arthur House, 18, was arrested on Monday after allegedly confessing to slaying and raping 35-year-old homeless mother Jessica Gibson in Baltimore last week

An 18-year-old man has been charged with raping and murdering a homeless mother before allegedly sexually assaulting her corpse.

Police said James Arthur House was arrested in Baltimore on Monday when he allegedly confessed to slaying and raping 35-year-old Jessica Gibson.

The mother-of-four's body was found dumped behind large pallets on a downtown Baltimore access road last Wednesday.

Police say she had been sexually assaulted and strangled.

Investigators do not yet have a motive for the crime, but they say House and the victim were known to each other. Their exact relationship is not yet clear.

Surveillance footage from around the area showed House and Gibson interacting before the attack took place.

After the victim's body was found, police released surveillance video of House inside a convenience store saying they believed he was the last person to see Gibson alive.

The teenager called 911 to hand himself in after spotting the footage of him on social media.

Jessica Gibson, a 35-year-old mother of four (above with her children), was found raped, strangled and murdered in Baltimore last week

House handed himself over to police after authorities released surveillance footage (above) of him in a store prior to the attack. They had said he was the last person to see her alive

House was charged with murder, rape, perverted practice, reckless endangerment and sex offenses.

Some of the sex acts House is charged with were allegedly carried out on Gibson's dead body.

'His confession was complete. Very sad,' Baltimore City Police Commissioner Kevin Davis said. 'Our victim was sexually assaulted in a most brutal way.'

While Gibson was homeless, police say she did have surviving relatives including her four young children.

Police spokesman T.J. Smith said: 'She had some of life's issues going on. Of course, that doesn't make her any less of a victim.'

Gibson's relatives have set up a GoFundMe page to help cover the cost of her funeral.

The mother-of-four's body was found dumped behind large pallets on a downtown Baltimore access road (pictured above) last Wednesday