At the end of last week, the Human Rights Commission of Malaysia announced it would be holding a public inquiry into the disappearance of two pastors, Raymond Koh and Joshua Hilmy, Hilmy's wife Ruth Sitepu and social activist Amri Che Mat.

The disappearances have cast a shadow over Malaysian civil society. No one has been held to account, and there are fears the kidnappings mark a new level of violent intolerance in the Muslim-majority country. So what has happened to the three Christians and one Muslim – and why?

Amri Che Mat is described as a 'social activist' and a Shia Muslim in a state where Sunni Islam is dominant. He was accused of spreading Shia teachings, though his wife has denied it.  He was last seen in November 2016.

The Hilmys also went missing in November. Joshua Hilmy is a former Muslim.

Pastor Koh was abducted on February 13, taken from his car, which was never recovered, by a group of men. Extraordinarily, the attack was captured on video and shows seven vehicles and at least 15 men involved in the action. The incident lasts for only 40 seconds, but subsequent footage appears to show an uninvolved car being warned off and directed away from the scene.

One man is in custody in connection with Koh's kidnapping, accused of approaching his family for a ransom. It is unclear, however, whether he had anything to do with the abduction. In June, police said they had found an unexpected link during an operation against a smuggling syndicate – photographs of Koh's house and his two vehicles were found at the home of a suspect killed during a shootout, according to the Malay Mail Online.

Meanwhile, a group comprising 48 civil society organisations, Citizen Action Group On Enforced Disappearance (CAGED) has been formed to put pressure on the government over the disappearance cases. Its spokesmen have been warned by police after accusing them of complicity in the kidnappings. Thomas Fann told the Guardian: 'We say that there is a high probability there have been enforced disappearances, which means that the state may be directly or indirectly involved.

'We have a reason to believe that there is a relationship because they are all faith-based workers.'

The police have denied the charge.

Malaysia is about 60 per cent Muslim, with Buddhists at 19 per cent and Christians at nine per cent. While freedom of religion is guaranteed by the constitution, in some parts of the country there is opposition to non-Christian religions and a rise in Islamism. A bitter court struggle has taken place over the right of Christians to use the word 'Allah' for God, with Islamists arguing it should be for Muslims only; while a 'Muslims only' laundrette in Johor state was condemned by the authorities for promoting extremism.

While there is no evidence Koh and the others were abducted for religious reasons, there's no evidence they weren't either – and it's the absence of any rationale that fuels worry among Christians. More than seven months after Koh's abduction, there is still no news – and for the others it's even longer. If a public inquiry can shed any light at all on what's happened, grieving families will welcome it.