The arrest of the “Bangalore techie,” as newspapers are calling him, is among the first cases to appear in court since last December, when India’s Supreme Court reinstated the 1861 law. The decision seemed to reverse a period of gradual liberalization in Indian society, including a decision by Delhi’s high court that the law violated constitutional guarantees of equality, privacy and freedom of expression.

Rights activists said the case could represent a dangerous precedent, because the sexual acts involved had been consensual and because the woman had invaded her husband’s privacy.

“What should have been seen simply as a matter of the man cheating on his wife, which would have essentially been a matter of civil dispute, has now become a criminal matter where the state is intruding on a person’s privacy,” said Danish Sheikh, a Bangalore lawyer who met the defendant on Thursday, when he was released on bail after four days in judicial custody.

This is the second case to be prosecuted in Bangalore since the Supreme Court judgment, following that of a doctor who was blackmailed by five men with whom he had had sex. The men were booked on charges of extortion, blackmail and Section 377 violations, while the doctor was also charged under Section 377. The case is currently on trial.

The “techie” case could prove more useful as a challenge to the Supreme Court ruling that restored the criminal penalty for gay sex, Mr. Sheikh said, since it does not involve abuse of power or extortion, which the court has dismissed as grounds for scuttling the law.