A Detroit man who was accused of building an arsenal in a terror case is facing 10 years in prison.
Sebastian Gregerson pleaded guilty today to charges of unregistered possession of destructive devices.
Gregerson was arrested in the summer after trying to purchase explosives from an undercover agent.
In an indictment unsealed in federal court, Gregerson, aka Abdurraahman Bin Mikaayl, 29, had been charged with receipt of explosive materials with intent to harm, two counts of unregistered possession of a destructive device and unlicensed receipt of explosive materials.
According to the indictment, Gregerson received the explosives, which contained 26 ounces of Composition B, a combination of TNT and RDX, "with knowledge and intent that said explosive materials would be used to kill, injure, and intimidate a person."
The complaint chronicles a counterterrorism investigation that began in April 2015 following a tip that Gregerson, who the FBI said also is known as Abdurrahman bin Mikaayl, had weapons.
The complaint said Gregerson earlier purchased "an arsenal of weapons, ammunition, tactical gear and tactical training materials."
It doesn't say whether Gregerson was planning an attack or why he was purchasing explosives.
His sentencing has been set for June 30.