THE grandmother of an unarmed black man shot dead by police in Sacramento, California, last week has called for change in the way police confront suspects.

Sequita Thompson gave a press conference on Monday night and recounted the events of March 18, when Stephon Clark was shot 20 times in the back garden of her house, where he lived.

“They didn’t have to kill him like that, they didn’t have to shoot him that many times,” she said.

Police claim they were pursuing a suspect who had broken three car windows and a neighbour’s door, and that, when challenged, Clark fled and refused to show his hands. Ms Thompson believes he was trying to return home when he was killed.

Recordings appear to show officers thought he was armed, although he turned out to be carrying only a mobile phone.

The National Association for the Advancement of Coloured People (NAACP) said Sacramento police department should change its regulations to allow officers to wait for backup, send in police dogs when a suspect is cornered, maintain surveillance or use non-lethal force such as Tasers.

“We’re always open to conversation on how we can do things differently or better and this case is no different,” department spokesman Eddie Macaulay said.

NAACP California president Alice Huffman said the organisation has asked the US Justice Department to investigate Mr Clark’s death and called on the state to appoint an inspector-general to investigate police-involved shootings. US police officially shot and killed 987 people last year, a figure roughly in line with previous years.

Mr Clark’s family have engaged lawyer Benjamin Crump, who described his death as the “execution” of a man who “chose non-violence.”

Mr Crump previously represented the families of Trayvon Martin, the teenager followed and shot dead by neighbourhood watch volunteer George Zimmermann in 2012, and Michael Brown, the Ferguson, Missouri, resident killed with his hands up pleading “don’t shoot” in 2014 — leading to mass protests against police violence using the slogan “hands up, don’t shoot.”

“No family should have to endure this suffering,” he told the audience, meeting cries of “amen!” and “enough is enough.”