South Australian police have launched an internal investigation after a video emerged of officers pinning down an Indigenous man who was hit several times.

Several clips shared on Monday night show SA Police officers forcefully handcuffing 28-year-old Noel Henry, who is being held on the ground against a fence.

In one video, filmed from behind the incident, one of the officers can be seen striking the man as two others help restrain him.

Bystanders, who filmed the footage, called for the officers to “get off his head” and “get his head up off the ground”.

SA Police has conceded that one officer appeared to strike Mr Henry and launched an investigation, which “has been taken very seriously”.

“A senior police officer has been assigned to undertake this as a matter of priority,” it said in a statement on Tuesday.

“As part of the initial review, the man has been released from police custody and the incident is the subject of further investigation.”

• Police to investigate violent arrest of Indigenous teenager

Police Commissioner Grant Stevens said the video had “caused concerns in terms of the police response” and a thorough investigation would be completed by a “very senior officer”.

He said the officers involved had been put on administrative duties.

Mr Henry was arrested and charged with hindering police, resisting police and property damage.

Comment on the social media post suggested he was stopped for not wearing a helmet while riding a bike.

However, a SA police spokesperson said officers attended the Kilburn address, in Adelaide’s inner-north, about 9.30pm on Monday for an alleged high-risk domestic violence incident where a woman was hospitalised.

They said officers saw a man leaving on a bicycle as they approached the property and searched him because they were suspicious he was carrying illegal drugs.

“The man originally was compliant and after a short time, he began to refuse. Police attempted to arrest the man who resisted and a struggle ensued,” the spokesperson said.

“Police and the man went to the ground as police attempted to restrain and handcuff him.”

Witness Emma Pereira said her friend Noel Henry was the man arrested in the driveway of her Albert Street flat. He was “getting tackled” by two officers when she started filming.

“He’s like part of our family, he’s lived in Kilburn for all his life,” Ms Pereira told The Advertiser.

Aboriginal rights activist and social worker Latoya Rule was sent video of the incident by witnesses.

She said Mr Henry spent the night at the Port Adelaide police station, but charges against him were dropped and he was released on Tuesday morning.

Ms Rule said Mr Henry had injuries to his head, arms and legs.

“He is alert at the moment, which is excellent,” she said.

But she remained concerned for his welfare.

“The police’s behaviour is very aggressive, very unnecessary and – in fact – is exacerbating the poor relationship that Aboriginal and Torres Strait Islander peoples already have alongside black and other Indigenous people and people of colour with police,” Ms Rule said.

Less than a fortnight ago, tens of thousands of people – including more than 5000 in Adelaide’s CBD – marched in calls for justice over the death of US man George Floyd and an end to indigenous deaths in custody.

Ms Rule’s brother Wayne Fella Morrison — a 29-year-old Aboriginal man — died in the Royal Adelaide Hospital on September 26, 2016, days after being pulled unconscious from a prison transport van.

She said the Australian response to the BLM movement was indicative of the experience of First Nations people with police.

“These relationships have never been formed on solid foundations of trust … what we’re seeing as a response from the community is that we’ve had enough, they can’t get away with this,” she said.

“They [First Nations people] don’t feel safe, they don’t feel like they protect us and the videos last night is a result of this – it just happened to be recorded.”

-with AAP