Carlos L. Rivera bragged about starting a fire that destroyed an Academy Street apartment building and referred to himself as "El Fire" the morning after the blaze, according to testimony Thursday in Jefferson County Court.

Travis G. Dunn, a former Fort Drum soldier now living in Texas, said he encountered Mr. Rivera about 8 a.m. Dec. 8, about five hours after fire destroyed 201-205 Academy, a fire Mr. Rivera is accused of setting.

Mr. Dunn admitted he had bought cocaine from Mr. Rivera and distributed it on his behalf, as well as having shared drugs with Mr. Rivera, whom he knew as "Lito." He said he met with Mr. Rivera at a friend's apartment Dec. 8 and "he told me personally, himself" that he had set the fire.

"He said that, 'They call me El Fire' and that he had burned down that building," Mr. Dunn said.

Mr. Dunn was among three witnesses who testified during the third day of Mr. Rivera's arson trial that he admitted starting the fire. Jennifer L. Watson, a friend of Mr. Dunn, said she also heard Mr. Rivera say he set a fire at the "Red" building while at the home of an acquaintance identified only as Jay.

"He came in and said that there was a fire and that he started it and he was freaking out about it," she said.

Mr. Rivera's attorney, Eric T. Swartz, as he has with most of the prosecution's witnesses, attacked Mr. Dunn's and Miss Watson's credibility. They were arrested together Dec. 23 for cocaine possession and both admitted heavy drug use as well as selling drugs for Mr. Rivera.

Mr. Dunn said he was discharged from the military owing, in part, to mental illness. Miss Watson said to Mr. Swartz that she "probably" was doing drugs when she heard Mr. Rivera's alleged admission.

Justin A. Parker said he had used marijuana before he encountered Mr. Rivera walking down Gotham Street carrying a backpack sometime early on Dec. 8. He and a passenger, identified as Jeffrey Cooper, picked Mr. Rivera up in Mr. Parker's vehicle and gave him a ride to a Union Street apartment.

Mr. Parker said he had loud music playing in his vehicle when he overheard Mr. Rivera and "Coop" mention a fire. He then accompanied the two men to the Union Street apartment, where "Lito just kind of disappeared." He said Mr. Rivera's absence "kind of weirded me out" because he was the only person other than Mr. Cooper whom he knew at the residence.

He said Mr. Cooper told him that Mr. Rivera had said something about setting a fire, but that there was nothing for Mr. Parker to worry about. Mr. Parker and Mr. Cooper stayed at the apartment for about 30 to 40 minutes and then drove back past 201-205 Academy St., also known as the Victoria Building, where "I see the whole Vic building on fire."

He said he returned home and "just kept getting phone call after phone call" about the fire and began to worry that he might be implicated in it for giving Mr. Rivera a ride. He spent about an hour looking for Mr. Rivera on the morning of Dec. 8, finally locating him on Jefferson Street, where the pair talked in the street.

Mr. Parker said Mr. Rivera told him he had been "beefing" with Joseph P. Puparro, in whose Victoria Building apartment the fire started. Mr. Parker also said he had observed a disagreement between the two men a day earlier, when Mr. Puparro kicked Mr. Rivera out of his apartment.

"I asked him, 'Bro, what happened?'" Mr. Parker said. "He said, 'I set his bed on fire, but I didn't mean for the whole building to catch on fire.'"

He said he Mr. Rivera told him he was leaving for the New York City area, where he was arrested on unrelated charges in his hometown Bronx on Dec. 23. Watertown Police Detective Sgt. Richard C. Wood said he went to the Bronx County Courthouse on Dec. 24 to bring Mr. Rivera back to Watertown.

He said that in the car on the way back to Watertown, Mr. Rivera asked, "How much time am I facing?" and Sgt. Wood offered an opinion.

"He started to cry," Sgt. Wood said. "He was concerned about being away from his family for that length of time."

Jurors also heard Wednesday from a city firefighter who said he had to ask Mr. Rivera twice to get out of his way so he could back a ladder truck to the rear of the Victoria Building during the fire. Steven K. Russell said Mr. Rivera's face was partially obscured by a cell phone when he yelled down from his truck, but later, after seeing news coverage of Mr. Rivera's arrest, he realized who the person was he had seen standing near the fire scene.

"Right at that time, it came to me that that was the gentleman I had to ask to move," Mr. Russell said.

Testimony in the trial will enter its fourth day Monday.