Nine police officers have been sentenced to death in India over the deaths in custody of a father and son in 2020.

P Jeyaraj, 58, and his son Benicks, 38, both died in jail in the southern state of Tamil Nadu - days after they were detained for allegedly keeping their mobile phone shop open in breach of lockdown rules during the Covid-19 pandemic.

The two men were stripped and ruthlessly assaulted in front of each other, the sentencing judge said on Monday - describing the case as a clear abuse of authority.

"They did this with the intention of killing," he said.

The officers, who were found guilty of murder last month, will be able to appeal against their sentences.

"They attacked unarmed people. They should not be forgiven. They should not be given lesser sentences based on their age or family background. They are all educated," the judge also said of the officers at sentencing.

Ten police officers in total were arrested over the brutal deaths of the father and son but one of the accused died of Covid in 2020.

The case triggered protests in Tamil Nadu, with state opposition lawmakers among those who took to the streets.

Opposition leader Rahul Gandhi and Indian cricket star Shikhar Dhawan were among those who demanded justice for the two men on social media.

The deaths also brought the issue of police brutality in India back into the limelight.

Rights groups say hundreds of people die while in custody in India every year. They point out that torture and abuse to extract confessions from suspects have become part of policing.

Earlier this year, several UN experts called on India to undertake major reforms to modernise policing in line with international human rights standards.