A line of new row houses is rising slowly out of the mud and ashes in the 6200 block of Osage Avenue, site of the nation's bloodiest urban battlefield of the 1980s. The MOVE compound, where seven adults and four children died, is a skeleton of new boards and bricks.

Five months have passed since police dropped a bomb on the row house headquarters, igniting a fire that burned out of control for six hours, destroying 61 homes and damaging scores of others in a middle-class neighborhood of west Philadelphia.

As a special commission prepares to open a month-long series of hearings Tuesday into the assault on the radical group, the mystery about what happened on Osage Avenue May 13 and why remains murky.

Piece by piece, official explanations of events that day have fallen apart. Subplots, accusations and hints of a cover-up have diverted attention from the key questions:

Why was a bomb dropped in a city neighorhood? Why didn't firefighters try to control the blaze for more than an hour? Why weren't attempts made to save children? Who made basic decisions? What did Mayor W. Wilson Goode know about the decisions, and when?

The 11-member Philadelphia Special Investigation Commission, appointed by Goode, has come under fire. Three commission members contributed to the mayor's campaign; firms employing other commission members do business with the city.

"The whole thing smells bad," said Richard Costello, recording secretary of Lodge 5 of the Fraternal Order of Police, which has filed lawsuits trying to halt the investigation.

"Can you image a murder defendant picking all the jurors in his trial? Can you image the results if Richard Nixon would have picked everyone on the Senate Watergate committee? What we have is a king being investigated by the palace guard," he said.

Commission Chairman William H. Brown III said the impression "that this would be nothing more than a whitewash" has put "a lot of pressure" on the panel to conduct a "fair and impartial investigation." The commission, he added, is composed of people who "aren't about to throw their reputations for the friendship of the mayor or anyone else."

"We want to show the world what happened, why it happened and what kind of planning went into events leading up to May 13," he said in an interview. "We want to know to what extent efforts were made to get children out, why officials thought the confrontation had to end the 13th, not the 14th or the 18th, who was in charge? Was it a police operation, a fire department operation or a mayor's operation, and who made the basic decisions?"

Brown, a black Republican, served as chairman of the Equal Employment Opportunity Commission in the Nixon administration. Among other commission members are former Watergate special prosecutor Henry Ruth; Neil J. Welch, a former head of the New York office of the Federal Bureau of Investigation, and three clergymen.

The hearings are to be held in a 600-seat television studio amphitheater and broadcast live, beginning to end, on public television. In a city whose two daily newspapers are strikebound, organizers are describing the hearings as a local version of the Senate Watergate committee hearings.

It is fitting. Most of the major elements of the confrontation between MOVE, a small band of self-described "back-to-nature" revolutionaries, and the city were played out on television. It was riveting drama, full of violence, tension and tragedy. Anyone with a TV set could watch events on Osage Avenue unfold.

Later, at televised news conferences, the city's first black mayor and other city officials could be seen explaining their actions. Goode initially took "full responsibility" for what happened but later the wall of unity by the mayor and top aides cracked.

City Director Leo Brooks, a retired Army general and Goode's top aide at the scene, resigned. Police Commissioner Gregore J. Sambor complained in one interview that, in months before the confrontation, "the administration was sitting on its posterior, not doing a damn thing" about the group, which antagonized its neighbors daily.

Goode began distancing himself from aides. On July 19, he said he considered himself responsible only "to the extent they other top officials followed my plan. To the extent they may be in deviation to that plan, they have to be responsible."

Use of a bomb to end a day of siege, he said, "was not a part of any plan that was ever discussed with me."

Goode remains popular with voters, but the hearings appear to put him in a no-win situation. If he is found to have been more involved in decisions than he has admitted, he will be accused of misleading the public. If his involvement is shown to have been minimal, questions will arise about his ability to control city government.

"To many in the business community, MOVE is a metaphor for a lot of other things -- indecision, lack of planning, scapegoating and back-stabbing," said one respected civic leader, who asked not to be identified. "What it really represents is the operating, management inefficiency about everything Wilson touches."

Disclosures also put the careers of Sambor, Fire Commissioner William Richmond and other officials in jeopardy. Among the disclosures:

*The fire. Sambor originally said MOVE members started it with gasoline in the house. Examination of videotapes of the incident by The Philadelphia Inquirer and a fire marshal's report concluded that the bomb, dropped from a helicopter at 5:27 p.m., ignited a gasoline can visible on the roof of the house.

Sixty-five minutes passed before any attempt was made to fight the fire, which was not declared under control until 11:27 p.m.

*The bomb. Police originally said the makeshift device contained two pounds of Du Pont Tovex, an explosive gel normally used in mining. But investigators found that it weighed 4.5 pounds and contained C4, a powerful military explosive.

Sambor, who had repeatedly denied that C4 had been used, said the police officer who built the device used C4 without his superiors' knowledge.

*The deaths. Parts of 11 bodies, including the children, were found in the wreckage of the heavily fortified MOVE compound. The city medical examiner concluded that all died in the fire, but there are indications that one or more may have died earlier in a day of gunfire and battering with fire hoses.

One police sergeant has said he saw an arm hanging limply from a body during a police assault on the compound that morning. In addition, commission pathologists learned that a metal fragment was found in the remains of one victim.

In an interview, Brown said the fragment may have killed the MOVE member and may have resulted from the explosion of an earlier police device, which it "appears contained C4."

*The children. Brown said investigators have determined that police made no effort to urge MOVE members to allow the escape of children after an evacuation order at dawn.

A shootout began shortly after the order, followed by an all-day siege. Police were armed with a .50-caliber machine gun, seven Uzi automatic weapons, 16 M16 semiautomatic rifles, two .22-caliber rifles with scopes and silencers, an antitank gun and 38,790 rounds of ammunition, according to records.

One child, Birdie Ward Africa, 13, and an adult, Ramona Africa, 29, escaped through an alley after flames engulfed the compound. Brown said the boy, expected to testify at the hearings, told investigators that two other children left the house ahead of him but that what happened to them is unknown.

Police officers have said they saw a man with a rifle emerge from the blaze, fire at them and disappear in the smoke. But firefighters at the scene reported no gunfire and no armed male.

Meanwhile, bills from the confrontation mount, posing added problems for the Goode administration. Each of the 61 row houses being built costs $110,000, and the city is repairing 82 homes in the surrounding neighborhood. Estimates of total costs to the city reach $10 million.