Polish leader Gen. Wojciech Jaruzelski today assumed direct supervision of the communist party apparatus in the Ministry for Internal Affairs, which oversees police forces.

Announcement of the move, which followed a meeting of the Politburo, the party's highest ranking decision-making body, made no mention of whose duties Jaruzelski had appropriated.

But the action appeared intended to strengthen the general's immediate control over internal security services, which have been stunned by murder indictments against several police officers for the killing of a pro-Solidarity priest, the Rev. Jerzy Popieluszko.

Jaruzelski's additional powers seemed to be taken at the expense of the authority of Miroslaw Milewski, a Politburo member and party secretary with overall responsibility for the security services.

Milewski, a career policeman, is associated with hard-line elements that have been thrown on the defensive by Popieluszko's murder.

Jaruzelski is already first secretary of the ruling communist party, prime minister, chairman of the Military Council of National Salvation and chief of the armed forces.

In a related development, the Internal Affairs Ministry said today that the three officers arrested for abducting Popieluszko Oct. 19 -- Capt. Grzegorz Piotrowski and Lts. Leszek Pekala and Waldemar Chmielewski -- have been charged with the priest's murder and have pleaded guilty.

A colonel who supervised the three officers has been charged with helping them, and the general heading the department in which they served has been suspended for poor supervision. Additionally, a lieutenant colonel in the Warsaw militia faces possible internal disciplinary measures for involvement.

The Polish Press Agency (PAP) carried a report given to a legislative committee by Internal Affairs Minister Czeslaw Kiszczak on the findings of the government's investigation into the killing.

The minister said the involvement of the three secret police functionaries in the murder is "undisputed." He said the three, masquerading as militiamen making a routine drunk-driving test, pulled over a car carrying Popieluszko and his driver, Waldemar Chrostowski, near Torun, about 130 miles northwest of Warsaw.

The driver was summoned to the militia car, where he was handcuffed and gagged, while Piotrowski "overpowered" Popieluszko and put the priest in the trunk of the militia car, which bore false license plates, Kiszczak said.

As the car sped away, Popieluszko's driver jumped out but the kidnapers ignored him. They drove to Wloclawek, about 40 miles to the southeast, and there took Popieluszko out of the trunk and dumped his tied-up body into a reservoir on the Vistula River.

Kiszczak quoted the abductors as saying the 37-year-old priest showed no sign of life when he was tossed into the water.

Kiszczak said the autopsy findings on Popieluszko are not yet complete, awaiting the result of laboratory experiments that will reveal the exact cause of death.

But the head of the ministry's investigation office, Col. Zbigniew Pudysz, was quoted by the PAP as telling the committee today that Popieluszko's death "was probably the result of strangling caused by pressure by hand, rope or gagging which interfered with breathing."

Kiszczak said equipment used by the kidnapers, including the false plates on their Internal Affairs Ministry car, had been found in Lake Czerniakowski in Warsaw.

The three kidnapers, he said, had tried to divert suspicion by falsifying the car's log, asking people to help create alibis and sending a ransom note to the church demanding a large sum in dollars.

The investigation could be closed now "if we didn't want to find other perpetrators and potential inspirers, if they exist," said Kiszczak. Polish authorities have repeatedly hinted at the existence of a wider conspiracy behind the attack on Popieluszko, possibly aimed at destabilizing Poland and weakening Jaruzelski's position.

Word of Jaruzelski's assumption of party command at Internal Affairs was limited to a sentence in a PAP report on the Politburo meeting. It said: "The Politburo recognized it as expedient that the first secretary, Gen. Wojciech Jaruzelski, personally assume the supervision over the party work in the Ministry of Internal Affairs."

Party leaders reaffirmed their "confidence" in the ministry, the dispatch said, calling the death of Popieluszko "an isolated event" that "must not undermine the good name of the state services."

They attacked opposition activists who were said to be trying to "exploit" the death to cause "internal disturbances," and complained specifically about some priests who "to this end use congregations of people in places of religious worship."

Without providing specifics, PAP said the Politburo approved new measures "designed to make impossible anti-state activities under one label or another."