The Palestinian English teacher who on Sunday transformed the observation deck of the world's most famous skyscraper into a bloody corral of chaos and death bought his semiautomatic pistol in a Florida gun shop the same day that he obtained a state residence card.

Mayor Rudolph W. Giuliani (R) said today that Ali Hassan Abu Kamal, 69, was described by his West Bank family as unbalanced after having lost his life savings in an American business scheme.

City and police officials said there was no evidence that Abu Kamal was linked to Middle East terrorism, and his family in Gaza said Abu Kamal was not political. Police Commissioner Howard Safir called Abu Kamal "one deranged individual working on his own."

Tonight, Associated Press reported that a high-ranking police source said a rambling note found in Abu Kamal's pocket blamed the United States for using Israel as "an instrument" against Palestine. It also expressed anger at France and Britain and indicated that Abu Kamal planned to vent his anger at the Empire State Building, according to AP.

In response to the AP report, Safir issued a statement calling the letter "rambling and disconnected." He said it stated Abu Kamal's "anger and dissatisfaction with a number of individuals, nationalists and occupations. . . . " But he reiterated that there was no evidence to support a conclusion that "Kamal acted other than alone. . . . "

Kamal arrived here last Christmas Eve, then traveled to Melbourne, Fla., establishing residency by staying briefly in a motel and paying about $500 for a 14-shot Beretta handgun. Abu Kamal shot seven sightseers at the Empire State Build ing's 86th-floor observation deck, one fatally, before killing himself.

"What sense is there in handing a murder weapon, an attack weapon, which is what this is, over to a man who is a transient living in a motel which I think could be described as a fleabag motel?" Giuliani asked. "I mean, that is totally insane."

Safir said the letter is "a further confirmation of why he should never have been allowed to purchase a weapon in Florida."

As the angry mayor used the tragedy to conduct a seminar on gun control laws, the Empire State Building shut its observation deck for one day.

The management said that by Tuesday it will have installed metal detectors and set up a system for searching bags of the 3 million tourists who each year ride express elevators to the 86th floor of the 102-story tower. For nearly 50 years, the Empire State Building reigned as the world's tallest building, and it still looms as perhaps the single most identifiable icon of 20th century American engineering.

The top of that icon on Sunday afternoon became a iron-fenced chamber of terror as tourists, many from foreign countries, ran from an elderly man muttering in English about Egypt and shooting indiscriminately.

A 27-year-old Danish rock musician was killed, and six others -- five of them foreigners -- were wounded. Matthew Gross, 27, of Montclair, N.J., remains in critical condition at Bellevue Hospital with a head wound.

In the Palestinian-governed West Bank, the family of the gunman said Abu Kamal had no connection to Palestinian terrorism. They described him as a conservative man with no strong political or religious views.

Family members and friends in Gaza City told New York police that Abu Kamal, an accomplished English teacher who saved a substantial amount of money from private tutoring, had been cheated in New York out of his life savings, which they estimated at $400,000 to $500,000. Officials said he came here on a tourist visa obtained in Tel Aviv.

Police cautioned, however, that they had no way of confirming this amount or how the money was lost.

Abu Kamal briefly established residency at the low-budget River Oaks Motel in Melbourne, Fla., motel owner Gary Gregory told the Associated Press. He was nicknamed "Papa" by people at the motel and was described as a kind but befuddled old man, occasionally standing naked outside his room. After he moved out, a motel employee told AP that she found needles and insulin, a protein hormone used by diabetics, in his refrigerator.

Giuliani seized on the Empire State Building shooting as a high-visibility platform from which to extol the falling crime rate in his city, defend tough local gun control laws and lambast those states -- Florida in particular -- that he said are "exporting their guns to New York."

"The problem that the Police Department is now facing is one created outside the city and the state of New York by places that allow people to get guns under which no check is done, no inquiry is made, and that should end," said Giuliani, who is seeking reelection this year.

Responding to Giuliani's charges about "irrational and insane" gun control laws, Florida Gov. Lawton Chiles (D) said "it is far from true to say Florida is cavalier on the way we treat the sale of guns.

"I think that Florida has a tough gun law. We were one of the first in the nation to do background checks. We've denied over 40,000 felons the right to purchase guns," Chiles said.

Florida law requires "instant checks" of a prospective buyer's criminal record and, like the federal Brady law, requires a three-day waiting period.

Gun shop owners in Miami said today that most buyers of guns purchased legally in Florida use their state driver's licenses as proof of residency. If the buyer does not have a driver's license, many gun shops say they also accept telephone or electric bills and a photo identification.

Giuliani said today that Abu Kamal picked out his Beretta on Jan. 30, the same day he was issued a photo identification from the state of Florida, which listed his address as a motel.

"He just shows up in Florida, gets a residence in a motel, walks in and walks out with a gun than can kill 14 people in three or four seconds. That is just absurd. That makes no sense," Giuliani said. Police here said Abu Kamal waited five days (the three-day waiting period plus a weekend) before collecting his purchase.

Florida destroys records of background checks on gun buyers within 48 hours and has no record of the original check, said Liz Hirst, a spokeswoman for the Florida state police. Since Sunday's shooting, the state has run another background check on Abu Kamal and found that he had no criminal background, she said.

"This Ali Hassan Abu Kamal -- and we ran it several different ways -- had no criminal history," she said. "He would not have been nonapproved due to criminal history. There is a federal requirement, above the state requirement, that an alien reside in the state 90 days." That would be a question for the federal Bureau of Alcohol, Tobacco and Firearms, Hirst said.

Federal law says that an alien must be in residence in one location for 90 consecutive days before legally buying a handgun. But a prospective gun buyer is on the honor system in filling out a federal form attesting to the residency requirement. An ATF spokesman in Washington refused to comment on whether the ATF was aware that Abu Kamal had obtained his residency document after less than a month in Florida.

"Obviously the system is no system at all," Giuliani said. Special correspondent Catharine Skipp in Miami contributed to this report. CAPTION: In Gaza City in the West Bank, Fathitya Abu Kamal, left, widow of Ali Hassan Abu Kamal, who shot seven people on the Empire State Building's observation deck Sunday with a 14-shot Beretta before committing suicide, poses with family members and a picture of her late husband. CAPTION: Abu Kamal, 69, arrived in New York Christmas Eve on tourist visa. CAPTION: A man photographs Empire State Building from street; observation deck was closed to the public.