A federal magistrate judge has ruled that the man accused of planting pipe bombs outside the Democratic and Republican headquarters the night before the 6 January Capitol attack must remain in custody while awaiting trial.

In a memorandum opinion, the court determined that Brian Cole Jr, 30, of Woodbridge, Virginia, “poses an intolerable risk of danger to the community if released”, granting the government’s motion for pretrial detention.

The judge wrote that “there are no conditions of release the court could impose to reasonably assure the safety of the community”, despite defense arguments that Cole could be placed under home detention with GPS monitoring.

Cole faces two federal charges stemming from allegations that he constructed, transported and attempted to detonate two improvised explosive devices near party headquarters in Washington on the evening of 5 January 2021. Neither device exploded and Capitol police safely disabled both, though the hunt for the perpetrator had been elusive since.

The charges – transportation of explosive devices across state lines with intent to harm and malicious attempted destruction using explosives – carry heavy penalties, with the latter carrying a potential 20-year prison sentence.

Cole’s defense attorneys argued that their client is on the autism spectrum and had “zero criminal history” and “zero evidence he will flee” in a recent court filing.

Authorities arrested Cole on 4 December, nearly five years after the attempted destruction. During searches of his Woodbridge home, police reportedly discovered several bomb-making components in a bedroom closet, including metal pipes, end caps and wire matching materials used in the 2021 devices.

According to court filings, Cole’s mobile phone interacted with five cell towers near both party headquarters during the timeframe when the devices were placed. A license plate reader also captured his vehicle leaving Interstate 395 in the area at about 7.10pm that evening.

Financial records allegedly showed Cole purchased nearly all the components used to construct the bombs from northern Virginia retail locations throughout 2019 and 2020. Prosecutors noted he continued buying similar materials into August 2022, after the attempted attack.

In a video interview following his arrest, Cole initially denied involvement before admitting he was the individual captured in surveillance footage, according to justice department documents. After agents reminded him that lying constituted an additional offence and asked again if he was the person in the video, Cole “paused for approximately 15 seconds, placed his head face down on the table, and answered, ‘yes’”, court papers state.

Cole reportedly told investigators he travelled to Washington to protest the 2020 election outcome and wanted to act against the parties because “they were in charge”. When asked why he targeted both party headquarters, he said: “I really don’t like either party at this point.”