Officers Jeff Walker and Linwood Norman marched down a blighted block of North Philly, straight toward an alleged crack supplier and an alleged street dealer who were about to make a deal.

The alleged supplier, Dmitrius Tolloiver, appeared to recognize the veteran undercover narcotics officers. He shouted, "Cops!" and then took off.

As two teams of undercover cops chased after Tolloiver Monday night, the alleged dealer, John Sullivan, 19, prepared for what could have been a fatal showdown.

Police officials said Sullivan charged toward Walker and Norman and fired a shot from a .45-caliber semi-automatic pistol that he had hidden in his jacket sleeve.

When the officers, who were standing just 5 feet away, weren't hit, police said, Sullivan squeezed the trigger a few more times, but his gun jammed.

"One officer was so close that he decided to tackle Sullivan instead of pulling out his firearm," said Capt. Chris Werner, head of Narcotics Field Unit 2. "There was a significant struggle for the gun."

But the struggle ended in minutes, and the cops took Sullivan into custody. A few blocks away, Tolloiver, 20, also was apprehended, and officers recovered $5,200 worth of crack cocaine, police said.

Werner said Sullivan, of Marshall Street near Susquehanna Avenue, and Tolloiver, of Franklin Street near Diamond, both were charged with attempted murder, aggravated assault, criminal conspiracy, resisting arrest and related charges.

Sullivan had been arrested in 2005 on weapons charges, and police said Tolloiver was himself a shooting victim that same year.

Werner said police developed information in the last week that a large crack delivery was going to occur on Franklin Street near Susquehanna Avenue. So, about 9:40 p.m. Monday, officers from Field Unit 2 were out in full force on the block, waiting for a deal between Sullivan and Tolloiver to go down.

It went awry when Tolloiver recognized Walker and Norman from having seen them in court. Both cops were wearing their badges and tactical vests Monday, but Sullivan "still decided to engage them," Werner said.

"Seconds feel like hours in a situation like that," observed Sgt. Joe McCloskey, who watched the scene unfold. "We're just glad everyone is OK." *