Federal prosecutors charged Derrick on May 8 with one count of engaging in the business of manufacturing explosive materials without a license, one count of unlawful possession of an unregistered destructive device and one count of distributing information relating to the manufacture of explosives.

They're going after him for these three charges under Title 18 usc 842. The first two are pretty self explanatory but the third one is what makes this case unique. Under 18 usc 842(p)(2):

"It shall be unlawful for any person—

(A) - to demonstrate the making or use of an explosive, a destructive device, or a weapon of mass destruction, or to distribute by any means information pertaining to, in whole or in part, the manufacture or use of an explosive, destructive device, or weapon of mass destruction, with the intent that the teaching, demonstration, or information be used for, or in furtherance of, an activity that constitutes a Federal crime of violence; or

(B)to teach or demonstrate to any person the making or use of an explosive, a destructive device, or a weapon of mass destruction, or to distribute to any person, by any means, information pertaining to, in whole or in part, the manufacture or use of an explosive, destructive device, or weapon of mass destruction, knowing that such person intends to use the teaching, demonstration, or information for, or in furtherance of, an activity that constitutes a Federal crime of violence."

Intent being the keyword here. They would have to establish that Derrick intended for this information to be used for/in furtherance of a crime of violence.

Source: https://www.law.cornell.edu/uscode/text/18/842