The Tokyo District Public Prosecutors Office's release Wednesday of three men suspected of involvement in the 1995 shooting of the then National Policy Agency chief demonstrates the dangers inherent in relying too heavily on confessions by suspects, and likely will lead to criticism of the police' handling of the case, observers said.
Test results of particles found on a coat believed to have been worn by the shooter and new testimony by one suspect failed to provide sufficient evidence for prosecutors to identify the perpetrator who shot Takaji Kunimatsu.
Consequently, the prosecutors Wednesday released three former Aum Supreme Truth cult members who had been arrested July 7 on suspicion of attempted murder.
Inconsistencies in the confession of Toshiyuki Kosugi, 39, a former police officer of the Metropolitan Police Department, threw the investigators and led them on a wild goose chase.
Prosecutors believed the shooting was organized and carried out by cult members, but had to release the suspects due to lack of evidence.
Some prosecutors criticized police investigations for placing too much weight on Kosugi's unsubstantiated confession.
Since spring 2002, when Kosugi was summoned for voluntary questioning by investigators of the special investigative headquarters of the Minami-Senju Police Station, Kosugi said he had been asked to take a coat to the scene of the shooting on the morning of the day the attack took place.
Kosugi also said he went to the scene with a man who appeared to be Satoru Hashimoto, 37, who was sitting in a car, and gave him the coat.
Hashimoto has filed an appeal with the Supreme Court against the death sentence he received for the killing of a lawyer and his family.
"The man got out of the car near the crime scene, but I was dozing in the car," Kosugi said.
When he confessed in 1996 to shooting Kunimatsu, Kosugi said he wore a half black leather coat on the morning of the shooting. But in his new confession, he said he was wearing a khaki coat.
He also said the coat he lent to the man was a dark-gray trench coat.
In 1996, investigators found small holes on the hem of a trench coat voluntarily submitted by Kosugi.
In April last year, the coat was examined at a synchrotron orbital radiation facility in Mikazukicho, Hyogo Prefecture, which revealed that particle elements around the holes matched particles found on the wall of a condominium building near the scene.
The investigators concluded that the coat's particles were not inconsistent with some bullets used in the shooting.
Based on this evidence, the investigative headquarters decided to arrest Kosugi, and two former senior cult members--Tetsuya Uemura, 49, and Mitsuo Sunaoshi, 36--on suspicion of attempted murder. Uemura's former surname was Kibe.
"Provided Kosugi affirmed the man he had lent the coat to was Hashimoto, we would be able to identify him as having been the shooter," a senior police officer said.
But on the morning of the day the shooting took place, there was no witness information to corroborate the car Kosugi said he had been in.
Kosugi also could not definitely say the man in question was Hashimoto.
With the exception of the fact that he had left a coat in a laundry near a Metropolitan Police Department dormitory in Bunkyo Ward, Tokyo, the remainder of Kosugi's confession could not be substantiated.
About two weeks after his arrest, Kosugi made several startling confessions, saying he might have shot Kunimatsu, that he was given a gun by an unknown male near the scene and returned it to the man after shooting Kunimatsu, and that he might not have lent the coat to the man.
The physical evidence the special investigative headquarters obtained from the examination of the particles raised the possibility of a man wearing the coat at the scene, but the evidence was not enough to positively identify the perpetrator.
Wednesday's release of the three suspects, and putting criminal charges against them on hold, shows that the investigation into the attempted murder has hit a brick wall more than nine years after the shooting.
Deputy public prosecutor Haruo Kasama said with the particles on Kosugi's coat as new evidence, suspicions that the cult had been involved in the case grew.
"That's why we decided to arrest them. The arrests made some headway toward solving the case," Kasama said.
But with the exception of these fragments of evidence, prosecutors relied mainly on Kosugi's confession to make their case.
Some prosecution officers believed the suspects could not be indicted when they were arrested because nobody knew who wore the coat at the time of the shooting.
When the arrests were made, prosecutors took the unusual step of stressing the arrests and indictments were two different matters, as the arrests were approved without the possibility of indictment.
They also said the arrests had been approved because there were no grounds to oppose making the arrests.
The crux of the matter was whether prosecutors could identify the perpetrator during investigations made after the arrests. Kosugi's confession that named Hashimoto as the person who pulled the trigger was unsubstantiated by other evidence.
Furthermore, with inconsistencies in Kosugi's confession, senior prosecutors were unable to alleviate their initial anxiety about the arrests.