A jury has found Ahmad Mohammed responsible for carrying out attacks on two Hull banks in the city centre last year.
Both Santander and Barclays were targeted at lunchtime on September 11th 2018.
A man described as carrying a knife and a petrol can went into Santander asking for money before throwing the petrol and igniting it.
He then went into Barclays to try and do the same, but did not manage to light the petrol. People ran from the building to try to get away, while some became trapped in the bank with him. Firearms officers arrived on the scene and eventually detained him at Hull Paragon.
During the three-day hearing at Hull Crown Court, the 25 year-old of Innsworth Garth, Bransholme was charged with attempted robbery, arson with intent to endanger life, three counts of possession of a bladed article, affray, criminal damage and threats to commit criminal damage in relation to the incident.