The man suspected of planting pipe bombs in Washington DC the night before the 6 January 2021 deadly attack on the US Capitol by supporters of Donald Trump trying to overturn his election defeat made his first appearance in federal court on Friday.

Brian Cole Jr, 30, of Woodbridge, Virginia, appeared before Magistrate Judge Moxila Upadhyaya Friday afternoon in Washington DC to face two explosives-related charges on the day after his arrest. Cole was accused of placing pipe bombs outside the headquarters of the Democratic and Republican parties not far from the US Capitol and the White House on the evening of 5 January 2021. Upadhyaya set a detention hearing for 15 December, with prosecutors expected to ask to detain Cole before trial.

Cole told investigators that he believed in conspiracy theories that the 2020 election won by Joe Biden over Donald Trump was stolen, reported CNN and NBC, citing people familiar with the matter. The Associated Press reported that Cole confessed to planting the bombs. The FBI and Department of Justice have not commented on Cole’s alleged motivations.

The devices were not discovered until the next day and were deactivated by police. Neither exploded and no one was hurt.

Cole was taken into custody on Thursday, the first suspect to be apprehended and named as the perpetrator by the authorities, after the justice department touted a break in a case that long vexed investigators.

FBI officials have said that dealing with the bombs required significant police resources as thousands of Trump supporters, many just coming from a rally by the then outgoing president urging them to overturn his defeat by Joe Biden, broke into the US Capitol in a failed attempt to stop Congress from certifying the results of the 2020 election.

Justice department officials have not provided a motive for pipe bomb incident or said if there was any link between the placement of the bombs and the insurrection at the Capitol, where lawmakers and staff had to flee for their lives.

Investigators traced purchases of several components used to make the bombs, including pipes, kitchen timers and battery connectors to Cole, according to an FBI affidavit laying out the evidence in the case.

Cellphone and license plate data also placed Cole in Washington near the Democratic National Committee and Republican National Committee buildings that evening, according to the affidavit.

The federal charges against him carry a potential sentence of up to 20 years in prison.

The US attorney general, Pam Bondi, said on Thursday that there was no new information that led authorities to Cole, but that a review of existing evidence led to the identification of the suspect.

Reuters contributed reporting