WASHINGTON — A defendant charged alongside members of the far-right Oath Keepers militia group in the Jan. 6 riot at the U.S. Capitol played down his message about ferrying “heavy weapons” across the Potomac River, calling it “creative writing” in testimony Tuesday.

Thomas Caldwell, 68, said he was never serious about trying to secure a boat to transport weapons across the river from a massive “quick reaction force” arsenal that Oath Keepers had stashed in a hotel room. His query about boating “heavy weapons” was among prosecutors’ most chilling pieces of evidence in the case that accuses Caldwell and others of a violent plot to stop the transfer of presidential power from Republican Donald Trump to Democrat Joe Biden.

“I do a lot creative writing and I just got out there,” Caldwell testified. Caldwell said the boat idea didn’t start with him, and he let it go after failing to find one. The guns never left the hotel room, but they’re a key piece of prosecutors’ seditious conspiracy case alleging the group plotted to block the transfer of power by force.

The defense has spent weeks hammering prosecutors’ lack of evidence of an explicit plan to attack the Capitol before Jan. 6, 2021. They say the Oath Keepers came to Washington to provide security at events for figures such as Trump ally Roger Stone before the president’s big outdoor rally behind the White House.

Caldwell took the stand as the trial against him, Oath Keepers founder Stewart Rhodes and three others was winding to a close after more than a month of testimony. It’s the most serious case to reach trial yet in the Jan. 6 attack that left police officers bloodied and bruised and sent lawmakers running for their lives. Closing arguments could happen as early as this week.

Prosecutors spent weeks methodically laying out how they say the Oath Keepers plotted for weeks to overturn Biden’s election victory by any means necessary.

Messages from Caldwell included a November 2020 missive after the Million MAGA March where he wrote that “we could have burned Congress down if we had wanted to” and another from shortly after the election raising the possibility of “civil war.”

On cross-examination, prosecutors showed messages that appeared to contradict his testimony, including his statement that he didn’t witness any violence when he and his wife entered Capitol grounds on Jan. 6. Caldwell responded he had been joking or exaggerating in his original missives, or sharing things he heard from others. At times, his explanations were confounding. For example, when prosecutors showed a video of his wife using a vulgar term in reference to Congress during the riot, he said she was trying to express that it was a “great opportunity to start the healing process in our country.”

Caldwell told jurors that his previous trips into Washington before Jan. 6 weren’t recognizance for an Oath Keepers operation but rather an effort to determine how many portable bathrooms would be available and where they would be.

Caldwell first met Oath Keepers members in November 2020, and grew close to them, allowing them to stay on his rural Virginia property. He didn’t officially join the group.

A disabled 19-year veteran of the U.S. Navy who suffered cracked vertebrae in the line of duty as a young man, he now copes with a range of physical ailments and uses a cane to walk as needed. He once had a top-secret security clearance and once worked for the FBI, his lawyer has said.

Defense lawyers have accused prosecutors of ripping Oath Keepers’ messages out of context to paint them unfairly.