The election last year of a dynamic left-leaning president generated hopes that Peru's chronic guerrilla violence could be defused by a program of economic development and judicious law enforcement promised by the young leader.

But in the aftermath of the government's suppression last week of uprisings by imprisoned leftist rebels at three prisons, prospects for domestic peace have been shattered and the authority of President Alan Garcia has been damaged both at home and abroad.

As bombings and killings continue to menace the capital -- in retaliation for the deaths of at least 266 jailed guerrillas -- the issue of security overshadows all others. The rebel threat to law and order is preoccupying Garcias' government, renewing friction between the 37-year-old democratic president and the armed forces and discouraging potential investors in this improverished nation's future.

Following the military's use of force against the mutineers, public attention is focusing more on Garcia's tactics than on those of the Sendero Luminoso (Shining Path) movement -- the fanatic pro-Maoist guerrilla group responsible for the uprisings and for much of Peru's terrorist threat.

The Peruvian leader, who tried and failed in his first months in office to achieve an opening with Sendero, has come under sharp attack from leftist opposition parties and the intellectual establishment for what they say was an impulsive unleashing of the armed forces against the prisoners.

In an open letter to Garcia published today, Peruvian author Mario Vargas Llosa said the government's action showed "a disproportion between the risk to democracy of the uprisings and the manner in which they were defeated that is morally and legally unjustifiable." The author suggested "more a settling of accounts with an enemy than an operation whose objective was to reestablish order."

To assuage critics, Garcia has authorized three investigations -- by the military, the attorney general and congress -- into the quelling of the revolt at Lurigancho prison, where 126 guerrillas died. There apparently were no Sendero survivors.

The investigations were announced Saturday night in a government communique that acknowledged that the number of dead "leads one to believe excesses in the use of force were committed . . . ." The inquiries are likely to irritate the security forces, whose relations with Garcia already were strained by a reduction in Army operations against Sendero and the firing of hundreds of policemen in an anti-corruption drive. Gen. Louis Cisneros echoed the discontent in military ranks in a magazine interview last week in which the former interior and defense minister complained that the government had not taken enough concrete measures to deal with terrorism.

For now, the inquiries are limited to the battle at Lurigancho, the country's largest prison located on Lima's outskirts. At the island prison of El Fronton, the siege was harsher, with a still-unofficial guerrilla death count of 138. But 30 guerrillas were reported to have surrendered and to have survived there.

At the Santa Barbara women's prison in Port of Callao, police units quickly reestablished control without military reinforcements. Two insurgents were reported killed there. The government has said the three uprisings were coordinated takeovers that began at 6 a.m. Wednesday.

Sources close to Garcia say the decision to use the armed forces -- in addition to police units, which had put down other rebellions by Sendero inmates in recent years with far fewer casualties -- was mosrist problem, meantime, remains linked to Peru's beleaguered economy. Until investor confidence can be restored and employment levels raised -- only one in three persons here has a steady job -- Sendero and the country's other guerrilla band, the urban-based Tupac Amarus, are expected to gain recruits in city slums and Andean villages.

Although Garcia has brought down the inflation rate and raised industrial output by fueling consumer demand, his more ambitious plans to decentralize the Lima bureaucracy and channel additional aid to poor agrarian highland regions have been frustrated by political and administrative resistance and a shortage of funds.