He calls himself an "urban combat correspondent":
He hops from one Baltimore crime scene to another in a beat-up taxi, using a blog and social media to discuss crime and police misconduct that he says the mainstream media ignore.
Lately, he had complained that the police were out to get him and had threatened on Twitter to kill any who tried. Over the weekend, they did come for him, serving an arrest warrant on an alleged probation violation connected to an old gun conviction. As promised, Frank James MacArthur did not go quietly.
As heavily armed tactical officers massed outside his North Baltimore home Saturday night, MacArthur streamed his hours-long telephone conversation with police negotiator Lt. Jason Yerg live over the Internet.
It's unclear how many people listened in, but the five-hour standoff nevertheless marked an apparently unprecedented development in the interaction of social media, digital technology and law enforcement, which is still adjusting to a world in which its actions are constantly photographed, videotaped and debated online.
By broadcasting the negotiation, MacArthur made public a sensitive conversation between police and a suspect, turning Yerg into an unwilling guest on a live talk show before peacefully surrendering in time for Saturday's 11 p.m. news broadcasts.
MacArthur was ordered held without bail on the alleged probation violation. Authorities said Monday that they were contemplating further charges related to the standoff and a sawed-off shotgun they said was in his house. Meanwhile, authorities have just begun to sort through the implications of usually secret talks streaming live — and whether that posed a danger to the police or made it more difficult to negotiate a surrender.
Police say Yerg didn't alter his tactics even as his every utterance could be heard across the Internet, although they also concede that the negotiations were prolonged as commanders tried to avoid using force.
"This will go right into the training scenario," said Elbert Shirey, a retired Baltimore deputy police commissioner and former commander of the tactical unit. "They will discuss this in classrooms and go through everything to try and determine how everybody reacted."
Situations in which suspects take to digital media during fast-moving situations are not unprecedented. This fall in Pittsburgh, a man who took a hostage in an office building posted about his ordeal on Facebook until police cut off his access, fearing it was interfering with their negotiations. But such measures are becoming increasingly difficult.
"Every individual around the country is now an instant broadcast station," said Robert Louden, a retired commander of the New York police's tactical division and a criminal justice professor at Georgian Court University in New Jersey.
Former Baltimore police commissioner Frederick Bealefeld said that what MacArthur did can distract police and the suspect and invites outsiders to intervene in the discussions.
"It takes away from creating a real connection and having a real dialogue with the person," Bealefeld said. "And all sorts of well-meaning people could interject themselves. It's fascinating to the people at home who have this sense of voyeurism, but it's also a significant hurdle for law enforcement."
With his tall frame and flowing dreadlocks, MacArthur stood out at police news conferences around Baltimore. He frequently sped to crime scenes, then taunted reporters who weren't there on Twitter.
He has said he has police sources, and while postings on his Baltimore Spectator blog have often been incorrect, he also has included details that indicate someone in the know was feeding him scoops. He knew in advance, for example, the date and time of the police department's secret plans to raid Occupy Baltimore.
A few years ago, when MacArthur had a radio talk show on WOLB (1010 AM), he invited Bealefeld to appear. But MacArthur also exhibited a deep suspicion of police, who he said were after him. Police were similarly wary of his tactics, concerned that he was more activist than journalist.
MacArthur was given probation before judgment on a 2009 gun possession charge, but state prison officials said he failed to show up to meetings with his probation agent, who charged him in June with violating the terms of his release. Officials say MacArthur then failed to show up for a court hearing, and a judge issued a warrant for his arrest.
MacArthur told Yerg during the negotiations that he had heard a rumor about the warrant and saw it in a public online database. But he also said he checked with his police sources and said he grew nervous when they could not find it. He said he intended to turn himself in, calling the warrant "a tripwire" meant to silence him.
Before his negotiations with Yerg, he had threatened police on Twitter. "Try to tread on me," one post read. "See what happens. See who's right and who's wrong. See who knows how to fight."
"Anyone trying to capture me, ur gonna have to kill me, before I kill you," he wrote in another.
As police neared his home, MacArthur tweeted: "Poor guy I take out might have a family."
Baltimore police said those threats led them to send the tactical team to his home. MacArthur said that was evidence of police unnecessarily targeting him, telling Yerg during their conversation that "as a taxpayer, I'm offended" at the resources sent to apprehend him.
MacArthur told Yerg that he didn't want to surrender because he couldn't trust the police.
"We live in a dangerous town, where your department can't even solve half the murders that take place," he told the lieutenant. "People like me wouldn't take on a marshal mind-set if you guys did more to make us feel safer. . . . We feel we're out here on on our own, lieutenant."
Yerg responded: "We're here because we genuinely want to help the citizens of Baltimore. We want to solve every crime that occurs. . . . That being said, we're here today . . . "
"To take me down," MacArthur interrupted.
Yerg said, "We want you to come out. "