SAN DIEGO -- FBI agents raided the apartment of an activist as part of an investigation into a $50 million arson fire in University City, it was reported Friday.

Slideshow

See Images Of Flames

Six agents searched the North Park apartment of 23-year-old Kathryn Dougherty Thursday, according to The San Diego Union-Tribune.

Dougherty and fellow activist Michael Cardenas, who was at the apartment during the raid, told the Union-Tribune they had nothing to do with the Aug. 1 arson that leveled a five-story residential complex under construction in University City.

Investigators began focusing on the militant Earth Liberation Front after a banner was found at the site that read: "If you build it, we will burn it," read the banner, which also bore the initials "E.L.F."

Dougherty said the raid was unnerving.

"I heard a pounding on the door about 7 a.m. Michael got up and opened the door. There were six FBI agents with guns drawn and a search warrant," she said.

Dougherty said when agents asked where the tape came from, she told them she got it at a recent rally.

The North Park home of activists David Agranoff and Cari Beltane was searched Aug. 14 by agents with the FBI and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives in connection with the arson investigation.

After three hours, agents left with a computer, documents, protest fliers, a video camera and videotapes.

Agranoff and Beltane, who run Compassion for Farm Animals from their home, said they had nothing to do with the fire.

Agranoff told the Union Tribune agents were seeking a videotape of activist Rodney Coronado, whom Agranoff invited to speak at a gathering on militant activism in Hillcrest Aug. 1.