18 April 2012 Last updated at 05:55 ET

Indian Professor Partho Sarathi Ray freed from jail

Partho Sarathi Ray denies participating in any protest

A molecular biologist who was arrested in India's West Bengal state for allegedly participating in a protest, has been freed after 10 days in jail.

Partho Sarathi Ray was arrested on 8 April for protesting against a slum eviction drive in Calcutta.

He says he was not even in the city on 4 April, the day of the protest.

More than 50 activists and academics from India and abroad wrote to Prime Minister Manmohan Singh asking him to intervene.

A well-known scientist, Prof Ray's work has been published in respectable journals around the world.

Police charged him with assaulting policemen during the protest, but he denies the charge.

His lawyers say he was at the Indian Institute of Science Education and Research in Nadia district to attend a faculty meeting on the day. They say he stayed there for the night and did not leave until the next day.

'Clear message'

His arrest was condemned by scientists and academics who wrote to Prime Minister Manmohan Singh asking him to intervene to secure Prof Ray's release.

"There seems to be a clear message to others not to raise voices of dissent," said the letter, signed by activists and academics including Aruna Roy, Nikhil Dey, Noam Chomsky, Mrigangka Sur, Abha Sur and others.

"This has implications for not only this series of events in Calcutta but also for democracy," the letter said.

The state government, led by Chief Minister Mamata Banerjee, has attracted a lot of negative publicity recently for cracking down on its critics.

Last week, police arrested a professor in Calcutta for allegedly posting on the internet cartoons ridiculing Ms Banerjee.

Professor Ambikesh Mahapatra, who teaches chemistry at Jadavpur University, was later released on bail.

Ms Banerjee came to power in 2011 bringing to an end the state's 34-year-old Communist rule.