The men were apparently related, but they shared more than a family tie.

Police said they were a tag-team of crime and violence, responsible for murder and robberies across the city. And they had vowed to resist arrest.

As officers and FBI agents swarmed their East Mount Airy hangout early Monday afternoon, the suspects stormed from a back door with weapons drawn, police said. The ensuing gunfight near Musgrave Street seemed to last 10 minutes, a neighbor said.

When it ended, 21-year-old Tevin Hammond was dead and 19-year-old Justin Mackie was severely wounded.

The shootout was not unexpected. According to Lt. John Stanford, a police spokesman, the department got a chilling response when it circulated word last week that the men were wanted: Hammond and Mackie told friends that they would not go quietly.

"They knew people were looking for them, and they made it very clear they would not surrender," Stanford said.

Investigators retrieved at least one gun believed to have been used by the suspects, Stanford said. But the police and the FBI were slow to release other details, because the probe was in its early stages.

Hours after the shooting, crime tape blocked off parts of Musgrave, and agents and officers combed the scene for evidence. An FBI review team was dispatched from Washington, standard practice during agent-involved shootings. Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives also joined the case.

Mackie was upgraded from critical to stable condition at Einstein Medical Center on Monday afternoon.

The suspects had been targeted by an FBI-led task force focused on violent criminals and fugitives.

Mackie was wanted in connection with a fatal shooting last week at 23d and Jefferson Streets in North Philadelphia. His face and case information were highlighted in Monday's issue of  the Philadelphia Daily News.

Hammond had at least one previous conviction for drug dealing, records show. Both men are also suspected in the shooting of a 53-year-old cabdriver last month, a law enforcement source said.

Late last week, police dispatchers broadcast an alert warning officers about the pair. According to that broadcast, both Mackie and Hammond sported facial tattoos, one with flames and the other symbols for "I love money." Dispatchers said one of the suspects appeared to walk with a limp, but that was because he hid a shotgun in his shorts.

Though he declined to discuss specifics, Stanford said they had left a trail of violent crimes. "Between shootings and homicides, well over a half-dozen . . . maybe a dozen," he said.

Neighbors said they did not know the men.

One, Eric Cody, was sitting on his porch around the corner when the shots started, popping as quickly as firecrackers but sounding more like cannons, he said. Cody hurried his two children into the house and told them to hit the floor, then he shooed off neighbors who were walking toward the commotion.

Cody said the neighborhood is generally quiet "except for a few knuckleheads."

The shooting was the third involving a Philadelphia officer in 24 hours.

Late Sunday afternoon, an officer near Fairmount Park shot a 17-year-old suspected drug dealer in the forearm after he feared the teenager was reaching for his service revolver, Stanford said. The suspect was treated at the Hospital of the University of Pennsylvania, and will be charged.

About 12:30 a.m., police fired on a car near the 1800 block of Bucknell Street after the driver pointed a gun at the officers, Stanford said. It was not clear if anyone was injured.

Contact John P. Martin at 215-925-2649, jmartin@phillynews.com or @JPMartinInky on Twitter.

Inquirer staff writer Robert Moran contributed to this article.