After eight months of testimony, the prosecution in the papal conspiracy trial summarized its case last week by arguing that "logical deduction" implicated the three Bulgarian defendants in the plot to kill Pope John Paul II even if hard evidence to substantiate the charge was still lacking.

Prosecutor Antonio Marini, four days into his final summation of the state's case, repeatedly reminded the two judges and six jurors on Saturday that "logical deduction" was admissible evidence in Italian law. Thus, Marini stressed, the logic of Bulgarian involvement should not be discounted because there was no hard proof tying the three Bulgarian officials to Mehmet Ali Agca's 1981 attempt to assassinate the pope.

Agca, the 27-year-old Turk who is also a defendant in the conspiracy trial taking place here in a heavily guarded former Olympic gymnasium, already has been convicted and sentenced to life imprisonment for shooting the pope in St. Peter's Square on May 13, 1981. The current trial is based on testimony that Agca began providing Italian judicial officials in jail in 1982.

While originally claiming that he acted alone, after a year in jail Agca began spinning a long, involved tale of a conspiracy linking Turkish rightists belonging to the "Gray Wolves" organization in Western Europe with Bulgarian intelligence agents who, he alleged, paid him 3 million West German marks (then about $1.2 million) to shoot the Polish-born pope.

As a result of Agca's prison testimony, four Turks and three Bulgarians were indicted in 1984 for conspiracy in the assassination attempt and their trial -- with one of the Turks and two of the Bulgarians absent -- began last May.

Once proclaimed the "trial of the century," it bogged down almost immediately because of the antics of Agca, who all but destroyed his credibility on the trial's first day with an impassioned proclamation that he was Jesus Christ. Throughout the trial, Agca's outrageous statements have undermined the state's case, built almost exclusively around his prison testimony.

In summing up the prosecution case in the past week and a half, prosecutor Marini argued that despite Agca's outbursts and contradictions, evidence of a greater plot had emerged.

On Saturday, Marini ridiculed the Bulgarian government for having at first denied that Agca ever had been in Bulgaria. He also questioned why Agca had been allowed to stay there when he was one of Turkey's most wanted men and had entered on an obviously forged Indian passport.

"One has to ask why the Bulgarians did not ask Agca on arrival, 'What sort of Indian are you?' " Marini said, raising his voice to a shout. "How could the Bulgarians claim they knew nothing about him? He stayed in four different hotels and showed a patently false passport in all of them. Why was the question never asked what sort of Indian he was?"