And he responds to questions on what the police are doing about it all.
"Remember what I said about the 47th St robbers celebrating the holidays early," he tweeted Dec. 23. "Hope they listened. One in custody. Two guns recovered."
Murray opened up his Twitter account in 2009 - 9143 is his badge number - and sees it as just another way to build trust and arm people with information.
"My goal was for people to actually know me - a detective they could pick up the phone and call," he said.
He's ahead of the digital curve in policing - perhaps a little too far ahead. His superiors asked him to suspend tweeting while they develop departmentwide policies and training - a directive Murray does not question. His approach may serve as a road map.
His tweets offer safety tips.
"We caught the shotgun robber," he wrote after a string of gas-station holdups. "Still try and use caution when pumping gas. Don't watch those annoying TVs."
He provides updates and information after violent crimes, like murders, and posts suspect photos and invites tips to his private e-mail.
Unlike the often-colorless wording of police reports, his tweets can pull back the curtain of policing: the carjacker who couldn't drive stick, the coward who shot a woman on Reinhard Street; a photo of a cat perched on his windshield while he serves a warrant.
Mike Lyons, cofounder of the community website Westphillylocal.com, says Murray's online accessibility and conversational tone soften the department's image and break down barriers between cops and residents.
"A lot of times you don't hear people talk positively about the police," Lyons said. "But in West Philly you do - and I think he's a big part of it. You almost feel like the guy has your back, the way he talks online."
But Murray has been off-line recently, which put a scare into his loyal followers. In January, a new police mandate required officers to get departmental permission before using their official titles on social-media sites.
Weeks passed. No word. No Fuzz.
Amara Rockar, a 26-year-old West Philadelphia resident, who has never met or talked with Murray but keeps his Twitter feed on her home page, circulated an online petition last week calling for the Fuzz's return.
A member of the Cedar Park Neighbors, Rockar says Murray's tweets lift the veil that separates police from those they protect.
"You got the sense that someone was there - that the police are actively doing work in the neighborhood," she said.
"Detective Murray's use of Twitter is exactly the kind of useful and positive police-community interaction that the Philadelphia Police Department should encourage," she wrote in her petition, signing it, "I want my TheFuzz9143."
Nearly 200 people signed it.
Any controversy was defused when the Fuzz's followers promptly received an e-mail from Karima Zedan, director of communications for the Philadelphia Police Department. Murray would be back online soon, Zedan explained. He wasn't being punished, just trained.
"Detective Murray's intentions were and are very good," she wrote. "We asked him to temporarily stop so that we could engage our social media efforts in a consistent manner across the whole department. I'm sure he will provide an excellent model for others to follow."
In coming months, the department will also roll out a new blog on its website, and a phillypolice.com smartphone application, Zedan wrote. Other officers are being trained to take advantage of social media, including the department's official Twitter feed, @Phillypolice.
Some of Murray's followers, who live in the neighborhoods southwest of University City, say Murray's tweeting has helped them organize into action.
In September, residents around 48th and Springfield, a neighborhood of stately Victorians, whose inhabitants include many professionals and students, held a meeting after the rape and robbery of a couple coming home from dinner. The residents invited Murray, whom they knew from Twitter.
In the past, the neighbors would leaflet doors with crime updates. The newly formed 48th Street Neighbors could now check Murray's Twitter feeds before heading out on their weekly bike patrols.
"He's helped us pick up a larger circle of folks beyond those of us who are doing patrols," said group member Kelvyn Anderson. "Not everyone can do patrols, or be at meetings, but through Detective Murray they can still have access to the intelligence."
Policing is in Murray's blood. He joined the force at 19, straight out of Father Judge High School in Northeast Philadelphia, making detective at 25. His grandfather was a patrolman, his uncles were on the job, and he is the son of Officer Joseph "Reds" Murray, 53, who carved his reputation in stone while working a beat in the 25th District, the Badlands, during the height of the crack explosion. Reds knew the 25th cold, veterans say.
The younger Murray began posting crime information on community blogs when he got to Southwest Division seven years ago - another tool of the beat, he said.
"It makes no sense to me to watch sitting ducks walk into a robbery pattern that I know about but they don't," he said.
When he opened a Twitter account, he identified himself as a detective, and posted for his profile picture a memorial photo of a friend and academy classmate, Sgt. Patrick McDonald, who was slain on duty in 2008.
"Hey everyone," he wrote in his first tweet. "Going to start posting crime patterns, wanted person and general public safety info. If I can be of any help let me know."
He posted his phone number and e-mail, and signed it, simply, "Joe."
Contact Mike Newall
at email@example.com, 215-854-2759, or @MikeNewall on Twitter.