Inquiry chair says he will investigate failings in the botched energy scheme "wherever accountability may lie".
There is a set-back in a plan to inspect all 2,100 boilers in the Renewable Heat Incentive scheme.
A timeline of events relating to the Renewable Heat Incentive scandal which caused the collapse of Northern Ireland's government.
Arlene Foster and Jonathan Bell's accounts are contradictory - how can we find where the truth lies?
BBC News NI answers commonly asked questions about the Renewable Heat Incentive scandal.