Kamal Valmiki, 25, was taken for questioning by Kanpur police 2 days before he died.

Highlights Kamal Valmiki had received severe injuries on his back and head

Police say he was found hanging in the lock-up

The family alleges he was beaten and hanged by the police

The Dalit man found dead at a police post in Kanpur on earlier this week, was severely beaten before he died, the postmortem report has said.The report notes that 25-year-old Kamal Valmiki, who had been picked up for questioning over a robbery on Tuesday night - had received severe injuries to his back and head.The man was found hanging in the lock-up. His family alleges that the police had severely beaten and then hanged him.The postmortem -- conducted by a team of specialised doctors on camera - says the man died due to suffocation.All 15 policemen at the post -- some of whom have gone missing -- have been suspended and a murder case has been filed against one.Kamal Valmiki's brother Nirmal, who was also picked up along with, has alleged that the police had threatened to kill his brother if he didn't confess to the crime.Nirmal was let off, but he said that for hours on Tuesday night, they were beaten with rods, abused and humiliated. "We were beaten as if we were footballs," he said."A custody death is absolutely unacceptable," Uttar Pradesh police chief Javed Ahmed had told NDTV.The incident had acquired political overtones with former Chief Minister Mayawati demanding action in the case. "A Dalit has died in custody. Only suspending policemen is not enough," she told reporters.The BSP chief, who is also a Dalit powerhouse, has pivoted her campaign in the coming assembly elections in the state on alleged atrocities against the underprivileged.