A man has been convicted by a federal jury for attempting to use a weapon of mass destruction at a downtown bank in Oklahoma City, the US Attorney's Office reported.

Jerry Drake Varnell, 24, of Sayre, was accused of trying to bomb BancFirst.

The jury took a half-day to deliberate and returned unanimous verdicts of guilty of attempting to use an explosive device to damage a building in interstate commerce and one count of attempting to use a weapon of mass destruction against a property used in interstate commerce. 

The FBI arrested Varnell early Aug. 12, 2017 after he attempted to detonate what he thought was an explosive laden van he had parked in an alley next to BancFirst, 101 North Broadway in Oklahoma City.

The arrest was the result of a long-term domestic terrorism investigation involving an undercover operation. 

The FBI first began investigating Varnell after they said he received a tip he wanted to blow up the Federal Reserve Building in Washington, D.C.,  with a similar device used in the 1995 Oklahoma City bombing because he was upset with the government.

Varnell will remain in custody until his sentencing which will be in about 90 days. He faces a maximum sentence of life for attempting use a weapon of mass destruction and a maximum of 20 years for attempting to use an explosive device. The minimum mandatory sentence for the latter conviction is five years. He could also be fined $250,000 on each count and subject to supervised release for the rest of his life, the U.S. Attorney's Office of Western District of Oklahoma said.