A dark blue, shabby pair of underwear was arguably the 'bomb' planted by the defence to rip through the case against an Australian national named Andrew Salvatore in Thiruvananthapuram, Kerala. He was found to be in possession of two packets containing charas, kept concealed in the pocket of his underwear at the Thiruvananthapuram airport, when he was headed to Mumbai in 1990.

When the trial began, Antony Raju, the counsel appearing for Salvatore, met the investigating officer K K Jayamohan, then the Circle Inspector of Poonthura police station, at the court verandah and told him about a surprise that would blow away the case.

"We have planted a bomb in the case, and it would explode once the trial was over, and then the case would be finished." Startled, Jayamohan was curious. He was told to wait and watch. Jayamohan, who was one of the prosecution witnesses in the case, later recollected the  exact line in the court. Antony Raju never conceded having made such a statement.

It didn't matter; he waited and watched the same bomb detonate after three decades on Saturday when the Nedumangadu JFMC-1 convicted him for tampering with evidence, which led to his immediate disqualification as the MLA.

While considering other crucial pieces of evidence in the case, Judge Ruby Ismail remarked that the 'bomb' reference cannot be considered as a casual or ordinary remark. "It clearly indicates that the second accused (Antony Raju) was referring to something within his special knowledge, which has the potential to destroy the prosecution case. Thus, it is of no doubt that the statement allegedly made by the second accused to the cop is a relevant fact," the court observed in the order.

It was ironic that the acquittal of Salvatore by the High Court set the events in motion which would later establish a serious break in the chain of custody of material evidence, the underwear. While the High Court overturned the conviction order of the Sessions court, Thiruvananthapuram, and acquitted Salvatore, it also observed that there was a strong possibility of underwear being planted in an attempt to help the accused wriggle out of the situation and ordered an inquiry.

The case then changed hands through five police officers. The last officer to probe the case was P Prabha, then Vanchiyoor DySP. He produced the message from Interpol, the letter from the CBI, the message from the Australian National Central Bureau to Interpol, New Delhi, the letter from Interpol, Canberra, which shed light on the possibility of evidence being tampered with by the counsels to materialise Salvatore's acquittal.

"The crucial aspect of the case was that, along with 51 personal belongings, the underwear marked as material evidence was also handed over to the counsel of the accused. It was in their custody for four months," said Assistant Public Prosecutor A Manmohan. The underwear was packed, sealed and produced in the court in April 1990 and then the first accused K S Jose, was present in the court. He even made the entry 'chest' against the item 'underwear'. Normally, only articles which can be converted into money, treated as valuables are placed in the treasury chest. The court noted that there was no need for the underwear, being a non-valuable item, to be put in the chest. By doing so, the clerk wanted everyone to conclude that the evidence was in the custody of the Junior Superintendent.

When the personal belongings of Salvatore were released from the court's custody in August 1990, the underwear was also included and it was returned only in December 1990. Antony Raju had signed the document and accepted the materials. Muhammad Wassim, who was the Presiding Officer of the Judicial Second Class Magistrate–II, Thiruvananthapuram, later stated that he became aware of the release of the underwear only when it was returned to the court by Antony Raju, with a submission that it had been obtained by mistake. Antony Raju told the court that he had met the Magistrate in his chamber, explained the matter, and, as directed by the Magistrate, an office staff verified and received the articles.

The prosecution relied on forensic evidence to prove that the underwear had been tampered with. The forensic report cited that the types of stitches and the threads used for the left and right vertical joints and the bottom cross joint were different from those used in the remaining portions of the underwear, which suggests tampering. The cutting of the label and its re-stitching onto a fragment of the same label also supports the inference of tampering.

The forensic expert further told the court that tampering could be specifically inferred from the stitching pattern, the lack of precision, the variation in alignment, and the presence of frayed fibres, which, according to him, suggest that the vertical stitches are hand-stitched, whereas the remaining stitches are machine-stitched. The court concluded that these alterations could only have occurred during the period when the underwear was in the unauthorised custody of the second accused.