Sandip Nathwani, who teaches in a local Pharmacy college, allegedly pushed his mother Jayshreeben to death on September 29 as he was "fed up" with her illness, according to police.
Initially, the Nathwani family had claimed that Jayashreeben fell off the terrace after losing her balance as she was suffering from some brain disease.
However, police changed the direction of the investigation on receipt of an unknown application. "After receiving the application, we checked CCTVs installed in the apartment and the recording clearly suggested that Sandip was with Jayshreeben when she fell off the terrace," said DCP, Zone II, Karanjraj Vaghela.
He said Sandip Nathwani initially denied the allegation against him, but later "confessed" to his involvement in the crime.
"He told us that he was fed up with his mother's illness. Sandip told us that on the day of the incident he took his mother to the terrace and pushed her," Mr Vaghela said.