A Missouri man who was killed last week was planning to set off a bomb at a hospital to further his radical white supremacist ideology, federal authorities said Monday.

Timothy Wilson, 36, died March 24 when the FBI sought to arrest him after a six-month investigation. A summary of the case in an FBI advisory sent to law enforcement Monday said he met with an undercover FBI employee and talked about setting off a vehicle bomb at a hospital because of "the increased impact given the media attention on the health sector" due to the coronavirus pandemic.

Full coverage of the coronavirus outbreak

Agents said Wilson bought several bags of fertilizer that can be used in bombs and kept them in a storage unit. They said Wilson and the undercover operative visited the hospital and discussed planning the attack.

On March 24, Wilson met the undercover at the storage unit and picked up what he thought was a working bomb but was actually an inert device constructed by the FBI. He was killed in a shootout when the FBI moved in to arrest him.

"Wilson had taken the necessary steps to acquire materials needed to build an explosive device," the FBI said last week in a public statement. Investigators "kept close track of Wilson in order to protect public safety."

The bulletin said he came under investigation in September, when the FBI arrested a Fort Riley, Kansas, soldier, Jarrett William Smith. Agents said Smith told others how to make bombs and talked about wanting to carry out attacks in the U.S. They said he and Wilson talked about how to make explosive devices "to further their racially motivated violent extremist ideology."

Smith pleaded guilty in February to distributing bomb-making instructions and will be sentenced in May.

The FBI said Wilson's plot reflects a trend among white supremacists who are "seeking to maximize their audience and the dissemination of their message."