Three officers were wounded when they entered Johnston's home looking for cocaine based on tips from an informant, according to the search warrant released Monday by the Fulton County State Court.

Police said the informant told officers he had purchased drugs in the home earlier, prompting investigators to get a warrant. But Atlanta Police Chief Richard Pennington said it was unclear whether there had been a drug deal or whether the suspected drug dealer actually exists.

"That's what we're going to have to investigate and determine," Pennington said. "The officers are saying one thing, the confidential informant is saying something else."

Monday evening, WAGA-TV aired an interview with a man who claimed to be the informant and said that he had never purchased drugs at Johnston's home. The man, whose identity was obscured by the TV station, also said that police had asked him to lie about providing the information, and he agreed -- but that was before he knew the elderly woman had been killed in a shootout there, he said.

According to The Atlanta Journal-Constitution, "From the beginning, it has been unclear why police targeted the woman's house, and the affidavit and warrant documents shed little light. The documents do not suggest that police had been keeping the house under surveillance and provide no rationale for entering it other than the informant's alleged buy earlier in the afternoon."

"The raid did not produce the cocaine, money, computers and other equipment related to the drug business alleged in the affidavit," the newspaper reported. "The documents listed the only resident as Sam, who was described as at least 6 feet tall and 250 to 260 pounds. Johnston's family said she lived alone."

Seven narcotics investigators and a police sergeant were placed on paid leave until the inquiry is complete, Pennington said. Pennington said the informant is in protective custody and would be a key part of the investigation.

"There are many unanswered questions," Pennington said. "I promise each and every citizen that the truth will eventually be known, but we must have patience."

After the shooting, officers said they found marijuana inside the northwest Atlanta home, but "not a large quantity," according to Pennington.

Police had a "no-knock" warrant, which are frequently used to get inside a home before suspects have a chance to get rid of drugs, said Pennington, adding that his department would review its policy on such warrants and its use of confidential informants.

The U.S. attorney's office, Georgia Bureau of Investigation and Fulton County district attorney's office also will take part in the review of the circumstances surrounding the shootout.

Johnston was described by neighbors and family as a woman living in fear in Vine City -- a northwest Atlanta neighborhood in the shadow of the Georgia Dome. There were burglar bars on her one-story brick home, and she rarely let friends and neighbors inside. .

The Atlanta-Journal Constitution reported Tuesday that "The Rev. Markel Hutchins, who has acted as spokesman for the family, said Johnston's family is encouraged by the FBI's entry into the investigation of the Nov. 21 gun battle that left Johnston dead and three narcotics officers wounded."

"They had zero confidence before yesterday," Hutchens told the newspaper. "Now their confidence is increased."

The Constitution also reported that "Mayor Shirley Franklin, who has said little publicly about the shooting, said she had discussed the allegations with Pennington." She expressed confidence that he police review process would be fair and thorough.

"I certainly share the concern that all of us have on the loss of life," Franklin said. "We were not expecting something like that could happen in the city of Atlanta."

Meanwhile in New York, Mayor Michael Bloomberg met Tuesday with the family of a man killed outside a strip club on his wedding day by a barrage of police gunfire, the second straight day Bloomberg has reached out to angry community members.

The 50-bullet police volley -- likened to a "firing squad" by the Rev. Al Sharpton -- killed 23-year-old Sean Bell on Nov. 25 after his bachelor party, wounded two of his friends and ignited concerns over police tactics and firepower. The three men were unarmed.

Bloomberg went to the family's church in Queens and met with Bell's fiancee and father, and with Sharpton. The mayor then met again with other community leaders.

On Monday, Bloomberg said the police response seemed "unacceptable" and "inexplicable," but he was steadfast in his support for Police Commissioner Raymond Kelly, who has been denounced by some critics since the shooting.

Of the victims, Bloomberg said Monday, "There is no evidence that they were doing anything wrong," referring to what led up to the moment their car struck an undercover officer outside the nightclub.

In contrast to Bloomberg's outreach, former Mayor Rudy Giuliani was hounded for what some viewed as a slow response to the killing of Amadou Diallo, an unarmed African immigrant who was shot 19 times in the entry to his apartment building by four white officers. Those officers were acquitted of criminal charges.

In an interview with Democracy Now, Diallo’s mother, Kadiatou Diallo, expressed her condolences to Bell's survivors as well as her confidence in those working closely with the affected families during this heartbreaking time.

"I have seen Rev. Sharpton standing up like the way he stood up for us when my son was killed, and other elected officials went with him to meet with the Mayor. I expect for them to continue to put pressure so that the community will receive justice," Diallo said.

"To the family, I hope that they can have proper representation, because it's a long road. It's a difficult one," she maintained. "You remember when the indictment was given to the four officers who were responsible for killing my son. After the indictment, we were hoping that the trial would happen in the Bronx where the crime happened. And the judge granted them a change of venue. I hope that this will not happen. Because had the trial happened in the Bronx, I think the outcome of the criminal case, when the officers who killed my son were tried, would be different, because they were acquitted of all charges."

Queens District Attorney Richard A. Brown said Monday his office was investigating the Saturday morning shootings, and the results would be presented to a grand jury.

Joseph Guzman, 31, was shot at least 11 times, and Trent Benefield, 23, was hit three times. Guzman was in critical condition, and Benefield in stable condition Tuesday.

The five officers have meanwhile been placed on administrative duties. They have yet to be interviewed by police officials. According to Commissioner Kelly, the officers were there staking out the club for prostitution and drug activity. Police sent two undercover cops inside where they apparently spent the next few hours nursing drinks and mingling with the crowd. Neither officer was given a breathalyzer test afterwards.

The shooting stemmed from an undercover operation that began 1 a.m. Saturday at the strip club Kalua Cabaret, part of a citywide crackdown sparked by the death of a teenager following a night of partying earlier this year at a Manhattan nightclub.

Police said they had received several complaints about prostitution and drug dealing at the cabaret and sent in two undercover detectives who left their guns behind because of searches at the door.

The detectives apparently spent the next few hours nursing drinks and mingling with the crowd.

Officials said the officers weren't impaired. "We authorize them to have two drinks, and not more," Kelly said.

One of the officers alerted the backup team outside that a man inside was possibly armed. An undercover detective retrieved his weapon and confronted Bell and his friends after they entered their car.

Kelly suggested that it was unorthodox for the officer to blow his cover rather than rely on other officers to make the arrest.

Union officials insist the detective took out his badge, identified himself and ordered the men to stop before the car, driven by Bell, lurched forward and bumped him. The vehicle then smashed into an unmarked police van, backed up and smashed the van again before the shooting began.

The crashes -- along with the fear that one of the men had a gun -- seem to be what escalated the situation to the hail of gunfire by five officers.