Two members of Saudi Arabia's religious police, or mutawa, are being questioned over the case of a man and a woman who were burnt to death in a car crash.
A relative of the man has told a Saudi newspaper that the couple were being chased by the mutawa when their car hit a lorry and burst into flames.
Officials say there is no evidence the two members of the mutawa were in pursuit of the car.
It is the latest in a series of controversies involving the mutawa.
The incident happened on Sunday in the northern town of Tabuk.
According to the newspaper Okaz, the religious police spied a man and a woman in a car and gave chase.
The car rammed into a lorry, burst into flames, and the couple were burnt to death.
The role of the mutawa is to prevent the mingling of the sexes, ensure that shops close at prayer times, and enforce the kingdom's strict dress code for women.
Although two members of the mutawa are being questioned over the case, the authorities insist that they were on a routine patrol - and that there is no evidence they were in pursuit of the car.
A series of controversies involving the mutawa have been publicised in the Saudi media.
Last year, in two separate cases, two men died while in their custody. In both cases members of the mutawa were acquitted.
However, in one of the cases, involving a young man allegedly beaten to death for making alcohol, a higher court has now overturned the not-guilty verdict and called for a fresh trial.
While many Saudis think the mutawa should be curbed, they continue to have powerful backers in both the ruling family and the religious establishment.