Although Chile's hard-line secret police was officially dissolved three months ago, it was not until recently that the first hard evidence came to light that the military government's vast inelligence establishment is in more moderate hands.

For the first time, the government disclosed that some former secret police agents were under investigation in connection with torture of political prisoners and that a number of soldiers have been convicted for abuses against civilians.

Human rights and diplomatic observers here remains skeptical after the dissolution of the National Intelligence Directorate, known by the acronym DINA, because a new intelligence organization called the National Information Central (CNI) was created and continued to operate out of DINA's headquarters with the same leaders and agents.

Still at his desk, although the title had changed to Acting Director of CNI was Col. Manuel Contreras, a protege of Chilean President Gen. Augusto Pinochet, and mastermind of the brutal DINA methods that decimated organized resistance ot the leftist parties that once claimed over 300 per cent of Chile's electorate.

Last Thursday, however, in a major power shuffle in the army high command, Contreras was moved up to general and out of the intelligence business. His replacement as head of the new intelligence service is retired Gen. Odlanier Mena, 51, the former head of regular army intelligence service whose abrupt retirement from active service in 1975 was linked to a dispute with Contreras about intelligence methods.

"It's optimistic," said a knowledgeable foreign diplomat, "the threat of a great secret police state is substantially changed."

The observers list other events pointing in the direction of more moderation:

A Santiago military court threw out a long list of DINA charges, including the accusation that the Catholic church's Vicariate of Solidarity was organizing "brigades" to overthrow the government, and released two men on suspended sentences after finding them guilty of possession of explosives. It was the latest of a series of findings by military judge Gen. Entrique Morel which rejected DINA evidence.

The suspended three-year sentences for Humberto Rouillas and William Zuleta were seen by human rights lawyers as symbolic punishments to allow the government to save face in an embarrassing case involving a 16-year-old boy's testimony that he had been kidnapped by DINA agents, then forced to confirm DINA charges linking Drouillas, Zuleta and three other men to the abduction. The other men were released earlier.

Human rights lawyer said they had been informed by military court officials that a military prosecutor is conducting a secret investigation against DINA agents alleged to have tortured the five men. The sources said the investigation was initiated at the request of Supreme Court President Jose Maria Eyzaguirre, who visited prisoners with a physician in May. It is the first official probe of alleged secret police wrongdoing.

Gen. Morel, who reportedly ordered the investigation, has emerged in recent months as unofficial spokesman for traditionally tight-lipped military to convey the message that security police abuses will no longer be winked at by military justice system. In the wide ranging shuffle in the army high command last week, Morel was named head of the Santiago area emergency zone and commander of the Santiago garrison in addition to his present posts of commander of the 2d Army Division and military judge.

In an interview. Morel said investigations were under way of alleged "abnormalities" commited by DINA and CNI agents, although he declined to go into detail or confirm the secret prosecutor's probe requested by the Supreme Court president.

Morel said many "lies" are printed in the foreign press about Chilean security forces, but he admitted there is usally a "few lines of truth" in the stories.

"We have been struggling a great deal to avoid this kind of cases," of alleged abuses he said. "I believe that abnormalities are committed and that each one of these cases is very detrimental. We investigate when there are concrete proofs, but not when it is just a matter of their word against ours"

Morel has granted a series of interviews with Chilean reporters in which he listed the convictions of 15 uniformed soldiers of abuses against civilians.

The cases did not involve secret police agents, but it was the first public admission of abuses by soldiers since the military government took power in a 1973 coup. It was seen here as a signal that the military intended to police its agents more closely.

Morel said restructuring of Chile's security forces is not just a name change and that a "great number" of former Dina agents had been dismissed since August. He described "the new intelligence chief Odlanier Mena, as "very capable, ver evenhanded."

Mena, presently serving as abmassador to Uruguay, was expected to run the news intelligence service as a technical investigative organization rather than the semiautonomous repression apparatus that Dina had become.

Arrests of political dissenters still go on in Chile, about 60 in the last two months, according to reports received by the Vicariate of Soldiarity, the human rights defense groups. The difference now. Vicariate spokesmen say is that most of those arrested are released or put on military trial with at least a chance of establishing their innocence.Reports of persons being picked up by security police and simply disappearing have practically ended.

A spokesman for the Vicariate said that the recent court decisions and personnel changes are welcome and encouraging, "but the church's position is that as long there are not a clear set of laws and enforcement by civilian court, citizens' rights are not really protected."