Once, he dragged Wallace to a murder scene on Thanksgiving. When police tried to chase MacArthur off, he turned the camera on them.

"Both him and Larry Wallace for some reason decided that since they were cab drivers and got a sense from talking to 20 to 30 people a day in all walks of life — I call it a barber shop in a taxi — that they were able to hear what people were thinking in different neighborhoods. And they became dissatisfied with folks not taking a strong stance," said radio host Larry Young of WOLB, who often put MacArthur on his show.

On a self-promotional video, footage shows MacArthur approaching former Baltimore NAACP chapter president Marvin "Doc" Cheatham and surprising him with a microphone.

"This is just radio," MacArthur tells him. "I try to keep a dual personality going."

His personality at home seemed much quieter, neighbors said. A vegetarian and animal lover who kept rabbits and dogs for pets, he fed stray cats on his porch from a pink dish, said neighbor Autevia Hardy.

At 6-foot-4, with dreadlocks down his back, he was a conspicuous presence who walked around barefoot or in sandals. He grew collard greens and other vegetables in his garden and planted sunflowers on a vacant spot just up the street.

His sister said he planted vegetables and flowers on empty lots to spruce up Baltimore's blighted neighborhoods. He'd find good deals at Home Depot and buy flowers in bulk. But often his projects ended up trampled, Arthur said.

In 2008, a police officer on the 4300 block of Old York Road noticed MacArthur walking around in a black bandanna with a Russian SKS-45 semi-automatic rifle and bayonet slung over his shoulder. MacArthur told the officer that he was going after some kids who broke into his car, court records show.

Wallace said MacArthur told him he had called 911 after some kids broke into his house, and he was just chasing them away.

He was charged with unlawfully carrying a rifle on a public city street and carrying a dangerous weapon with the intent and purpose of causing injury. From central booking, he called Young's radio show to protest. He soon took to his blog to rant, and prosecutor Kurt Nachtman subpoenaed blog entries and other postings. Nachtman perceived the postings as threatening, he said last week.

MacArthur was sent to the Walter P. Carter Center, a psychiatric hospital, for more than a month. He eventually agreed to a plea deal and received three years of probation.

MacArthur has maintained he met all of its conditions, but in June his probation agent requested a warrant claiming he had failed to report in April 2011. MacArthur said he didn't learn of the warrant until months later when he took to Twitter and online radio to taunt police. "Anyone trying to capture me, ur gonna have to kill me, before I kill you. I'm a nice guy, but I'm a bad, bad man. Dangerous us, so don't try," he wrote Dec. 1.

Hours later police arrived outside his home. They had been monitoring his messages and called in SWAT when he failed to open the door. MacArthur waited until 11 p.m. to give up, hoping TV news would broadcast the arrest.

Police on the scene noted that his distinctive dreadlocks had been shaved off. He told them his home was booby trapped, according to an officer at the scene. So they went through windows and said they found a sawed-off shotgun, which led to charges of illegal possession of a firearm and possessing an unregistered shotgun.

His sister, Arthur, said she believes the gun was planted. Wallace also was skeptical. "I haven't seen a gun in his house, and I've been with him a lot of times," he said.

In court, MacArthur has said it was "hard to believe" that a gun similar to the confiscated gun he had four years ago reappeared in his house.

In court hearings, MacArthur said he went into hiding from "rogue officers." The fact that his Twitter posts are included in charging papers indicates the First Amendment is no longer valid, he asserted.

"If you had counsel," Circuit Judge Marcus Z. Shar said at a hearing Monday, "they may be advising you not to say anything."

"Your honor," MacArthur responded, "my counsel is God."

He told the judge that someone is "determined to silence this voice by any means necessary."

Baltimore Sun reporter Justin Fenton contributed to this report.