PORT-AU-PRINCE, Haiti, March 22 ? When Haiti’s new police chief made a surprise tour of six police stations in the capital earlier this month, they were nearly empty. Only about two dozen officers were on duty when there should have been nearly 200. “And they were in civilian clothes,” the chief, Léon Charles, said despondently.

As Haiti slowly emerges from weeks of violent political turmoil that led to the exile of President Jean-Bertrand Aristide, Mr. Charles and other members of the new interim government face the challenge of resurrecting the rule of law and ending official impunity. They plan to strengthen an emaciated justice system and to gut and rebuild a police force that is widely viewed as disorganized, demoralized, ineffectual and corrupt.

“There was effectively no police in the last two years,” said Mr. Charles, who until recently headed Haiti’s Coast Guard, working closely with the United States on drug interdiction and other issues. Of the 6,000 officers on the national police force’s payroll, he said, he can count on fewer than 2,000 to even show up, let alone provide law enforcement.

Officials of the new government and human rights activists say many police officers have been involved in drug trafficking, extrajudicial killings and kidnappings. Members of the Aristide administration often used police officers to punish opponents, those officials say.

“The system was used not to protect but to abuse and oppress,” the new minister of justice and public security, Bernard Gousse, said in a recent interview.

The interim government of Prime Minister Gérard Latortue, appointed on March 9 to lead Haiti to national elections, has moved quickly to track down officials in Mr. Aristide’s administration suspected of involvement in criminal enterprises. The government plans to pursue several criminal cases that had languished under Mr. Aristide, Mr. Gousse said, most notably the murder in 2000 of Jean Dominique, a leading radio commentator who criticized corruption in the Aristide government.

The new government is also planning to investigate abuses committed or ordered by the Aristide administration. Mr. Aristide’s opponents have accused him of human rights violations and embezzlement of state money. Officials say the government intends to build a criminal case against Mr. Aristide and could eventually seek his extradition back to Haiti to stand trial.

But Mr. Latortue, who has vowed to lead a nonpartisan government, will be closely watched for how he handles the accused and the convicted criminals among the ranks of his own government’s perceived allies. Human rights advocates in Haiti and abroad say they will not stand by if the Latortue administration abuses its own power.

That challenge came into sharp focus on March 20 in the coastal city of Gonaïves during a visit by Mr. Latortue and his top justice and police officials. In a raucous ceremony in the town’s central plaza, commanders of the rebel army that helped to drive Mr. Aristide into exile last month shared a stage with the government officials.

Among the rebel leaders was the notorious Jean-Pierre Baptiste, smiling and looking triumphant. It did not seem to matter that Mr. Baptiste, whose nom de guerre is Jean Tatoune, had been freed by rebels last year from a prison where he had been serving a life sentence for his participation in the killings of Aristide supporters in Gonaïves in 1994. Mr. Latortue hailed the rebels as “freedom fighters.”

The events provoked alarm among some rights advocates and international observers.

Jocelyn McCalla, executive director of the New York-based National Coalition of Haitian Rights, has denounced the “unholy alliance” between the interim government and the anti-Aristide rebels. They include Louis-Jodel Chamblain, who was convicted in absentia for the murder in 1993 of a pro-Aristide businessman and returned from a decade in exile in the Dominican Republic to lead the insurgency against Mr. Aristide. Mr. McCalla accused Mr. Latortue of “fanning the flames of lawlessness.”

Mr. Baptiste and Mr. Chamblain are among hundreds of accused or convicted criminals who are now freely walking the streets of Haiti. Some of them were released from prison by rebels in the final days before Mr. Aristide’s departure, including Prosper Avril, a former general who seized power in a coup in 1988 and had been in prison awaiting trial on charges stemming from a massacre in 1990.

[Mr. Chamblain said Saturday that he would kill Mr. Aristide if he returned to Haiti, Reuters reported. “If Aristide comes tomorrow I will have 15,000, 20,000 Haitians armed to fight him and kill him as he killed my wife,” said Mr. Chamblain, who accuses Mr. Aristide of ordering his wife’s death in 1991.]

Brian Concannon, an American lawyer who helped the Aristide government bring the case against Mr. Baptiste and others involved in killings, says that hard-fought gains in the prosecution of human rights violations are being reversed.

“Right now we’re back to less than zero,” Mr. Concannon said in a telephone interview from Oregon, where he lives.

Camille Leblanc, a prominent lawyer in Port-au-Prince and a justice minister under former President René Préval, said: “We are waiting to see what the new government will do about this. It is one of the major tests the new government will have to pass. If you say you are not going to do anything about these cases, it’s as if you are condoning the reign of impunity under Aristide.”

Officials of the new government have not said how they plan to treat anti-Aristide rebels accused or convicted of crimes. “There is a plan to bring to justice everyone who has broken the law,” Justice Minister Gousse said in a recent interview.

But, he added: “When society itself is in disarray, we have to heal some wounds. It’s important not to forgive everything but to understand what led them.”

Meanwhile, as Mr. Gousse and Mr. Charles push their new agendas to overhaul the justice and law-enforcement systems, they warn that the campaign could turn violent. An aide to Mr. Latortue said intelligence had indicated that assassins might choose top officials as targets in an effort to destabilize the new government.

Mr. Gousse now travels everywhere with a security detail. Mr. Charles still drives himself to work on occasion. But he expects that he, too, may soon be forced move only in a convoy of bulletproof vehicles packed with bodyguards.