Their focus was one house in the 6200 block of Osage Avenue, a block of two-story rowhouses with good-sized porches, many enclosed. There were trees along the curbs. This was not a block accustomed to crime or violence.
But it was here, on this block, at 5:35 a.m. on that May 13, that Police Commissioner Gregore Sambor, clad in the black raiment favored by assault troops, picked up a bullhorn and said, in his distinctive, flat tones:
"Attention, MOVE . . . This is America. You have to abide by the laws of the United States."
He was talking to the occupants of the house at 6221 Osage. Four people believed to be in there were named in arrest warrants, he said, and they had 15 minutes to surrender. Neither he nor anyone else on the outside knew for sure how many people were in that house, although it was believed the number included adults and children.
They were members of MOVE, the anti-society cult that lived by its own rules, ignoring the courts, ignoring police, ignoring health and sanitation codes.
Their neighbors had complained of being harassed by constant harangues over loudspeakers, of being sickened at the raw garbage thrown from the house, of being appalled by the sight of the unwashed, unschooled and often unfed MOVE children.
The neighbors had demanded that something be done. And now, the city was taking action.
In preparation, the Osage Avenue block and several surrounding blocks had been evacuated. Barricades had been placed to keep spectators at least a block away. In the middle of the night, the gas and electricity had been shut off.
What happened that day looked like war, sounded like war, had the bloodshed and the flames of war. Officially, it was just an effort by the city of Philadelphia to serve warrants on some undesirables.
Minutes after Sambor spoke - and after a vulgar "come and get us" refusal over MOVE's loudspeaker - firefighters turned on their water cannons, aiming at the bunker MOVE members had built on the roof.
As recounted in a chronology prepared for the report of the commission that studied the day's events, here's what happened next:
Tear-gas and smoke projectiles were fired at the front and rear of the MOVE house shortly before 6 a.m. Under that cover, police assault teams entered houses on either side of 6221.
At 6 a.m., the first shots were fired on police from the MOVE house. Police returned the fire. In fact, in the next 1 1/2 hours, they used 10,000 rounds of ammunition and had to send to the Police Academy for more.
At 6:18, the gunfire was drowned out by thunderous explosions. It was the assault teams, trying to blow holes in the walls of 6221 Osage.
Another heavy explosion at 6:51 was followed by more heavy gunfire.
The gunfire sometimes lasted for several minutes. By 7:30, it was virtually over, but the heavy damage had yet to begin.
Between 7:30 and 10:30, the teams inside the Osage Avenue houses set off more charges, severely damaging the fronts of 6217 and 6219 Osage.
At 10:40, the last charge was set off. It blew out the fronts of the MOVE house and the adjoining one at 6223.
Meanwhile, the deluge guns continued hammering at the bunker on the roof of 6221. Some boards were knocked loose, but the structure remained intact. Police feared it could still be used to direct fire at them.
As the battle raged, barricades kept reporters and bystanders more than a block from the action. But hundreds of spectators stood at those barricades, unbelieving front-row spectators at what had developed into prolonged open warfare on a city street. Thousands of others watched on television.
By 12:30 p.m., aware their actions had not dislodged the residents of 6221, police withdrew their assault teams.
At 3:45 p.m., Mayor Goode, at a press conference, said he intended to ''seize control of the house . . . by any means possible."
About that time, Sambor and Managing Director Leo Brooks decided they could not demolish the bunker with a construction crane. By 4:40, Sambor had instructed the bomb squad to assemble an explosive package, and, by 5, Goode approved the dropping of explosives on the MOVE house.
At 5:27, the bomb was dropped from a state police helicopter. There was a searing flash - caught on television cameras - as it exploded on the roof of 6221, near the bunker. The bunker, the report noted, was "not dislodged."
After that, inferno.
The water barrage had ended shortly before the bomb was dropped and was not resumed for more than an hour. By 5:42, there was heavy smoke on the roof of the MOVE house. Minutes later, flames.
By 6:15, the fire had spread to three other houses, and at 6:21, the roof of the MOVE house collapsed. No fire alarm had sounded, and no water was being poured on the fire.
At 6:32, the water guns went into action again, but with little effect. By 6:54, when the first alarm went off, much of the north side of Osage Avenue was in flames.
Five more alarms were struck by 9:34, when firefighters, for the first time, began attacking the blaze in the conventional manner. But the march of the flames was relentless; they crossed Osage on the trees.
Before long, the fire also engulfed the homes on the south side of Pine Street, the row behind the MOVE house. By 9 p.m., three rows of houses - two on Osage Avenue, one on Pine - were ablaze.
Meanwhile, at 7:35, stakeout officers in an alley behind the MOVE home saw a woman and young boy emerge from the house and took them into custody. They were burned and cut, but they survived. They were the only ones who did.
At 11:41, the fire was declared under control. But 61 houses had been destroyed, several others damaged. Most residents lost all their possessions.
It was hours, many hours, before police could enter the smoldering pile of bricks that had been 6221 Osage. It was weeks before medical examiners could sort out the bones they found and determine that 11 people had died there, five of them children.