The former US sailor accused of infiltrating government networks using the Navy’s own computers and posting links to his group’s findings on Twitter says he and his associates “did dumb things.”

Prosecutors allege Nicholas Paul Knight, 27, a former systems administrator in the US Navy’s nuclear reactor department of the USS Harry S. Truman, led a double life during his time as a sailor, leading a group of hackers called Team Digi7al that stole confidential information and would post it online.

“Essentially I am in trouble for posting all of the stuff on Twitter,” Knight told ABC News by email. “Although a lot of people are saying I was the leader of some crime organizations that was out to get people which wasn’t true. Just a group of people that were dumb and did dumb things.”

The group targeted high-profile US government websites – including the US Navy site and a Department of Homeland Security site – as well as various websites of the Library of Congress, the World Health Organization, and Harvard University, according to the single-count court records filed on Monday.

Prosecutors also say the group, with help from other members of Team Digi7al, hacked the Navy’s SWM database, which held information about 220,000 Navy sailors. Others alleged targets included the US National Geospatial-Intelligence Agency, a military mapping agency, and the Los Alamos National Laboratory, a government-run developer that build the atomic bombs dropped during World War II.

Team Digi7al would boast of their attacks on Twitter, with Knight, who called himself a “nuclear blackhat,” acting as the group’s top “publicist,” according to the US Department of Justice.

The court filing said three alleged members of Team Digi7al were minors when they joined the activities. One alleged member told investigators some in the group were “somewhat politically inclined” to release secret information. But the group was also out for “fun,” another alleged member said, “which, when you get right down to it, that’s what everyone does.”

Knight, who says he is not very political, was on duty aboard the Truman when he allegedly “conduct[ed] unlawful Team Digi7al activities on the Navy’s computer network.” Though the filing does not accuse him of trying to hack into the ship’s protected systems.

Knight did not deny he hacked into several targets, as the filing suggests, but he said none of those sites were related to the US military or government. He claims another member of the group – which Knight helped to catch – did most of the hacking while he posted the results.

The court filing said Knight, who was never arrested, agreed to cooperate with law enforcement after his home was raided in February 2013.

When a suspect is charged in a criminal information filing – instead of an indictment – it often indicates the defense will not contest the charges, prosecutor in the case Ryan Souders told ABC News.

“I did something dumb and am willing to suffer the consequences,” Knight said.

Knight says he was honorably discharged and “conducted [himself] professionally while on the ship.” Military records indicate he joined the Navy in 2009 and reported to the Truman in 2011. He was a Machinists Mate Third Class when he left the service in May 2013, shortly after his home was raided.

Knight says he is currently employed as a service specialist at Siemens. The technology firm confirmed Knight is an employee there but did not provide ABC News with further comment.

The Navy and the Department of Homeland Security did not respond to request for comment either.

Attorneys for Knight and Daniel Krueger, another Team Digi7al member named in the filing, did not respond to requests for comment.

If found guilty, Knight and Krueger, 20, could face up to five years in prison or a $250,000 fine, according to the Justice Department.