RHI inquiry hears a warning on potential exploitation of public funds was not shared with NI officials
More than double the number of RHI boilers were applied for in 2015 than officials expected, inquiry hears.
As the public inquiry into the botched Renewable Heat Incentive scheme begins, BBC News NI outlines what you need to know.
After almost 60 days of evidence the RHI inquiry has taken the public behind the scenes at Stormont.
BBC News NI answers commonly asked questions about the Renewable Heat Incentive scandal.