Police in Michigan, US, have arrested a man after footage emerged showing him violently beating up a 75-year-old elderly man in a rest home.
The distressing video shows the young man punching the frail man over and over again.
The footage was widely shared on social media, including by US president Donald Trump.
"Can this be real? Where is this nursing home? How is the victim doing?" Trump tweeted.
The man has been arrested and the 75-year-old is said to have escaped without serious injuries.
The attacker, who has not been named, is said to be a resident of the same care home, which also offers rehabilitation therapy.
It is believed he filmed the abuse himself on May 15.
A person who viewed the video called police, who visited the Westwood Nursing Centre. Staff were already aware of the video, which has raised concerns about a possible cover up.
The suspect has also reportedly posted another video showing the beating of a woman confined to a bed.
The man has been arrested and Detroit police are investigating.