A rash of fires, believed to be intentionally set to derail investigations into government corruption, have destroyed several buildings here and taken some lives.

In recent years, the arrival of auditors at government departments appears to have precipitated at least a dozen such fires, which mysteriously begin in accounting departments and spread to destroy entire office buildings.

An incendiary-bomb fire in January gutted Nigeria's four year-old external telecommunications headquarters, a building that is as distinctive on the Lagos skyline as are the twin World Trade Center skyscrapers on New York's. twin It is now a fire-blackened, 37-story, multimillion dollar ruin.

After the country's long spate of building fires, most thought to be set to cover up embezzlement, Nigerian President Shehu Shagari's initial business-as-usual reaction in an election year to the telecommunications high-rise fire shocked Lagos residents and, in part, sparked a violent antigovernment protest by university students, according to western diplomatic sources.

Many Nigerians watching the blaze on Jan. 24 openly wept, eyewitnesses said, at the destruction of what, for many, had become a tall symbol of the nation's progress.

But Shagari says that spreading corruption does worry him deeply.

"What worries me more than anything among our problems is that of moral decadence in our country," Shagari said in a recently published interview. "There is the problem of bribery, corruption, lack of dedication to duty, dishonesty and all such vices."

To begin to overcome Nigeria's moral decay, "we have to start with educating the public, and unless the public realizes the dangers and is ready to cooperate in fighting the evils, government can do very little," Shagari continued. "I don't think this problem is absolutely intractable, although it surely gives me a great deal of concern."

Before Nigeria's former 13-year military rule ended with the transfer of power to Shagari's elected civilian government in 1979, an investigation into the financial records of the Communications Ministry was ended when the accounts department was gutted by a fire of undetermined origin in the country's Post and Telecommunications building. The pattern was set.

A similar fire in 1980 left the Education Ministry's accounting department records in ashes. The same year, the Imo state government treasury building burned down. In Gongola state the following year, a probe into a $3 million fraud in the state's agricultural agency was halted by a fire that destroyed the accounting ledgers.

In one of the more spectacular fires in 1981, the 11-story Republic Building, housing Nigeria's External Affairs Ministry, burned completely to the ground over three days in mid-December in a fire that began in the ministry's ninth-floor accounting department, according to the report by the government's investigating tribunal.

An internal audit six months earlier found hundreds of thousands of dollars in unreconciled debits in the department's records. The investigation discovered also the "startling" disbursal of nearly a half million dollars by the accounting department the month before the fire, an expenditure for which an explanation "cannot now be given as the records were burned," the tribunal's report stated.

The accounting section's "chaotic state," the tribunal concluded, "was not only a mere possibility but the main reason why the building was set on fire." Two women, trapped on the 10th floor, died in the fire.

Late last year, the accounts department of the Federal Capital Development Authority was burned just after the start of an investigation into the alleged embezzlement of $21 million by the agency's staff. The authority is in charge of the construction of Nigeria's new $14 billion capital at Abuja, 330 miles northeast of Lagos. The agency's administrator and four other officials have been charged with embezzlement.

In the investigation of January's telecommunications tower fire, the government-owned newspaper New Nigerian reported Feb. 13, American arson experts established that the fire was sparked by three incendiary bombs exploding at the same time on the building's third, a middle-level and a top floor. Two people were reported killed in the blaze and 21 people, including top administrators, have been charged with arson and murder in connection with the fire.

An audit beginning last year into allegations of a multimillion dollar fraud in the agency was followed by anonymous threats months ago that the building would be burned down, according to Nigerian Communications Minister Audu Ogbeh. Firefighters were stationed with their trucks around the tower for several months but were inexplicably withdrawn in December. In early February, a Nigerian fire official and senior official with the Interior Ministry were charged with accepting a $75,000 bribe to withdraw the firefighters.

The day after the tower fire, hundreds of students from Lagos University were tear gassed by police officers while they demonstrated in the streets of the capital against the government, stormed the national assembly building three blocks from the scene of the fire and carried signs reading "no more trial by fire" and "Shagari out, military in," according to a western source.

Shagari had "caused a domestic shock" by leaving Nigeria for a scheduled visit to India the day before the demonstrations "literally while the building was on fire," the diplomatic source said. Besides the fire, which temporarily cut the country off from all external communications, Nigeria was going through the traumatic expulsion of about 1.5 million illegal aliens.

"Many of Shagari's advisers now see his trip at that time as a tactical error," the source added.

One of Shagari's main advisers, Transportation Minister Umaru Dikko, contended in an interview that the fires since the 1979 return to civilian government have had both a criminal "cover-up" intent and a political aim of discrediting Shagari's government. A knowledgeable western diplomatic source said that given Nigeria's history of "uncompromising" political opponents, Dikko's allegation is credible, especially with the charged campaign atmosphere in anticipation of this summer's state, federal and presidential elections.

While declining to name who he thought was responsible for the political elements of the fires, Dikko said that government officials under investigation for embezzlement "become fertile ground for those politicians and political organizations, registered or unregistered, that are bent on destabilizing our nation" because they have not won national office at the ballot box.

"Some of the government's political opponents think they can burn the country down and confuse the elections," said Dikko, whose National Party of Nigeria is thought to be way ahead of the other five political parties in federal races this year. "I'm not sure if people will be foolish enough to vote for those who wish to burn them."