The case followed several arrests across the country for political cartoons or comments made online.

Sunil Abraham, executive director of the Bangalore-based Centre for Internet and Society research group, said the "natural reaction" was to worry about the new police lab given the way the law has been used.

"Police in the last four years have acted in an arbitrary and random fashion, often using the IT Act to settle political scores," he told AFP.

"When there's no crisis for the police, proactively keeping an eye on what people are saying or doing is overkill," he said.

Choudhary said the lab was not set to censor comments, echoing a statement made by police commissioner Satyapal Singh at the launch.

"By reading the mindset of what people are writing on various modes of communication, we will try to provide better and improved safety and security to the Mumbai citizens," Singh said.

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