DACCA, Pakistan, Dec. 19 —Some 5,000 people witnessed the torture and execution of four young men at a public rally here yesterday.

None of the leaders of the Mukti Bahini, the guerrilla force that fought for the in dependence of East Pakistan, who were present at the rally could explain the specific charges against the four men.

“They are razakars,” said one, referring to the local militiamen who are, believed responsible for widespread killing, rape and looting, The razakars have been under West Pakistani command through the last nine months of strife in Bangladesh, as the Bengali secessionists call East Pakistan.

Yesterday morning before the executions, the mass graves of several hundred Bengalis, apparently mostly doctors, professors and students, were found near Dacca. All had been tortured and murdered—allegedly by the razakars—in the last days before the Pakistani Army's surrender.

The men, boys and Mukti Bahini soldiers who swarmed through the city for the rally at Dacca's Race Course saw tortured dead in almost every street. Some of the dead had just been slain, their throats cut.

According to Moslem custom, only men gathered for the rally beside the Race Course stadium. Mukti Bahini soldiers, dressed in an array of colorful uniforms and heavily armed, guarded the approaches to the speakers’ stand.

The four tied prisoners were dumped from a jeep be side the stand, and while speakers harangued the crowd in the staccato Bengali language, no one paid any attention to the four men.

A tall, bearded Mukti Bahini officer, Abdul Kader Siddiqi, called on the demonstrators to preserve calm and discipline and not to take the law into their own hands.

After the speeches a mullah, or Moslem priest, led the crowd in prayer, pleading to Allah for a peaceful future for a free Bangladesh.

Many men and soldiers cried openly as they raised their hands, palms toward heaven.

It was during the prayers that the ordeal for the men began. Unable to raise their tied hands to proper praying positions, they were abused by a few soldiers. One pulled their hair, and they were kicked and cracked on the head with rifle butts.

More and more blows came. The four men were beaten with clubs. The victims whimpered. A cheering crowd had to be beaten back with sticks by some of the guerrillas.

A tall, slim man in a black uniform and fur cap selected one prisoner, stood over him and then delivered karate blows at the head and genitals.

The beating went on for about 30 minutes, and the prisoners were still pleading for their lives, clinging to the legs and feet of their at tackers.

Then the main speaker stepped from the rostrum, and as the crowd fell silent he walked among the victims. Then he pointed his swagger stick. Two soldiers fixed their bayonets.

One soldier leaned back, aimed his bayonet and stabbed the man who had been pointed to. Then other soldiers joined in.

After a brief pause they began to work on the other three men, methodically and quietly. All the noise came from the surrounding crowd. The soldiers stabbed in the chest but avoided the heart. Legs, abdomen, throat and face were other targets.

The stabbing was briefly interrupted when the self styled general, Mr. Siddiqi, asked for a bayonet from one of the soldiers.

A Mukti Bahini soldier handed over his rifle and then propped up one of the bleeding men so Mr. Siddiqi could make some direct jabs into the chest.

One soldier fired a bullet from a submachine gun into the stomach of one of the men.

It went on for 10 minutes more. Then the soldiers wiped their bayonets, put them away and walked through the crowd to their vehicles.

The men still showed signs of life. A small boy, possibly a relative of one of the dying men, flung himself to the ground beside him. The boy was at once kicked and beaten with rifle butts.

Never during the incident did anyone take note of the dozen or so Western newsmen who had come to cover a political rally.

A newsman, who told Indian Army commanders about the killings said that the commanders were shocked and had promised that disciplinary action would be taken against those responsible.