Is it love or terror?

India's Supreme Court yesterday started hearing a case that prosecutors say shows how Islamic State sympathisers are using "Love Jihad" – marrying Hindu women and converting them to Islam – to win recruits and spread their message.

Over the past 28 months, the National Investigation Agency (NIA) has picked up dozens of interfaith couples in the southern state of Kerala to question them about their marriages.

The women - all Hindus who married Muslims – were asked "extremely personal" questions during the interrogations, two police officers from the agency said: "Did you sleep with your husband before getting married? Did he suggest you visit Islamic shrines before marriage? Did he blackmail you before you converted to Islam?"

They were looking for cases of "Love Jihad", a term publicized by the Rashtriya Swayamsevak Sangh (RSS) and other hardline Hindu groups soon after they helped propel Prime Minister Narendra Modi to power in 2014. It refers to what these groups say is an Islamist campaign to convert Hindu women through seduction and marriage.

Police investigations at the time found no evidence of any organised strategy, and the claim was widely ridiculed. But since then, the NIA began focusing on Kerala - a state along the Arabian Sea with strong economic links to the Middle East.

It investigated 89 cases of "Love Jihad" and found nine to be alliances planned by people linked to the Islamic State, two NIA sources said, requesting anonymity because the investigation is going on. The NIA will present evidence in the nine cases to the Supreme Court.

The agency declined to disclose its evidence.

Opposition parties say the investigation shows the government is allowing the RSS and others to use the state apparatus to further an agenda of establishing Hindu dominance in India, where 13 percent of the population is Muslim.

The RSS, which founded the first iteration of Modi's ruling Bharatiya Janata Party six decades ago, believes India is fundamentally a Hindu nation.

Since Modi's election in May 2014, the RSS has expanded its membership and influence across India and either it or its affiliates now run key ministries, such as the home ministry, which supervises the NIA, and the finance ministry.

Nearly half of Kerala's 33 million people practice Islam and Christianity. Police and the NIA said at least 100 people from Kerala have joined the IS in Syria, Iraq and Afghanistan.