Teen charged with murder after Instagram video chat - police

Joshua Cooper is accused of killing a teenaged girl, then seeking help on Instagram to dispose of the body

A US teenager has been charged as an adult after police say he killed someone and asked an Instagram friend for help getting rid of the body.

Police in Bensalem, Pennsylvania claim a woman told them on Friday that her daughter had received an Instagram video call from an acquaintance.

During the call, the 16-year-old boy "showed the legs and feet of someone covered in blood", police said.

"He then asked for assistance with disposal of the body", they said.

The suspect has been charged with criminal homicide, possessing instruments of crime, and tampering with or fabricating physical evidence.

Police have identified the boy as Joshua Cooper, a resident at a local trailer park.

When they arrived on Friday at the mobile home listed as the suspect's address, a young male was seen running out of the back of the trailer.

Inside, police found a teenage girl lying dead on the bathroom floor with an apparent gunshot wound.

"There were also indications that substantial steps were taken to clean up the crime scene," police said.

The victim's identity and age have not been publicly revealed, but the Philadelphia Inquirer - which acquired an affidavit of the suspect's arrest - reports that she was 13 years old and has been identified by the jewellery she was wearing when she died.

According to the Inquirer, the suspect cleaned out his father's gun safe, including reorganising firearms and sorting through ammunition, before the victim came over to watch a Netflix series together.

Shortly after his arrest, he told police the shooting was "an accident" and that his dad was going to kill him.

Police found the gun safe and a holster without a gun in a back bedroom of the trailer, the Inquirer reported, citing the affidavit.

The suspect has been denied bail and is currently jailed at a local juvenile detention centre.