Indian police have arrested a professor on the charge of murdering his terminally ill mother by throwing her off the terrace.

A chilling CCTV footage, which has emerged as crucial evidence, shows Sandip Nathwani, 36, taking his hobbling mother to the terrace of their apartment in Rajkot, Gujarat.

Jayashree, 64, who was partially paralysed due to brain haemorrhage looks emaciated and is unable to even stand on her own.

The video shows Sandip forcing her to climb the stairs at 8.30 am on September 27, 2017.

A few minutes later she was found dead, with her limp body lying in a pool dead on the ground of the apartment complex. The police initially believed that she had committed suicide, though there were doubts on how the severely ill woman had managed to reach the terrace on her own.

A few days ago, the police received an anonymous letter accusing Sandip of murder and a copy of the CCTV footage from the apartment.

Deputy commissioner of police Karanraj Vaghela said, " The role of her son then came under scanner after we received the CCTV footage."

Sandip maintained that he had only assisted his mother to the terrace as she wanted to pray there and had returned to his flat. But upon sustained interrogation, he broke down and confessed to his crime.

Jayashree had suffered a brain haemorrhage a few years ago and had become bed ridden. Her illness was reportedly a source of constant fight between Sandeep and his wife.

Jayshree was a retired schoolteacher and Sandip taught at a local pharmacy college.