The family of a 20-year-old Dublin man is trying to establish the circumstances surrounding his death in the US on Monday.

Andrew Hanlon, who is believed to be from Dundrum, was shot dead by a police officer in the small town of Silverton in the northwestern state of Oregon.

Speaking on RTÉ Radio's Morning Ireland, Mr Hanlon's sister, Melanie Heise, who lives in Silverton, said the circumstances surrounding her brother's death were the subject of much hearsay.

She said police told the family on Tuesday that Andrew had been shot dead but they had not contacted the family directly since then.

Ms Heise said there was a lot of anger about his death in the town, which has not had a shooting for 20 years. She said local residents had held a protest. They were appalled and wanted to know why excessive force was used, she added.

The funeral home had told the family that Andrew had suffered extensive injuries. She asked why a taser was not used instead of a gun.

Ms Heise said her brother had arrived in Oregon several months ago and stayed with her and her husband before moving out to live on his own.

She said it was at this point that she noticed he had psychological problems and had organised psychiatric treatment for him. She added that people who had seen him before the shooting said he appeared fine.

Ms Heise said her brother was not the kind of individual to keep a gun.

In the incident, it is believed the officer was responding to a reported burglary when he encountered Mr Hanlon and shot him. He died at the scene shortly after 11pm on Monday night.

An investigation is under way and the police officer involved has been placed on administrative leave.

The Department of Foreign Affairs has confirmed it is offering consular assistance to Mr Hanlon's family.

Listen to an interview with Andrew Hanlon's mother Dorothea Hanlon on RTÉ Radio One's Liveline