MUMBAI, Dec. 9 -- More than two decades after allegations of large-scale manipulation in examinations conducted by the Maharashtra Public Service Commission (MPSC) surfaced in 2001, the prosecution's case in a clutch of linked trials before a special court is showing visible strain, key witnesses are disowning statements, disputing signatures and citing fading memory. Over the last week, the court has recorded the depositions of several retired government officials who served as invigilators during the 1999-2001 examinations, as well as candidates whose results were allegedly tainted by malpractice. A recurring pattern has emerged, with witnesses denying that signatures on answer sheets are theirs, saying they can't recall events after 20 years, or retracting statements purportedly recorded by the ACB. The scam surfaced in 2001, after the MPSC conducted delayed examinations for the 1999 recruitment of Mantralaya assistants and other posts. Following complaints and internal scrutiny, allegations emerged that original answer sheets had been replaced with fake ones, that computer data relating to marks had been tampered with, and that interview scores were arbitrarily inflated. Based on these allegations, the Mumbai unit of the Anti-Corruption Bureau (ACB) registered a case in 2002 and took over the investigation, which later led to the filing of multiple charge-sheets and the clubbing of several connected trials. During the probe, 29 people were arrested, including then MPSC chairperson, SD Karnik, former examination controller Sudhakar Sarode, MPSC member Sayli Joshi, and deputy superintendent of police, Baban Kadam, among others. Among the witnesses examined last week was Jayprakash Mansaramji Ambade, a retired Mantralaya official who later rose to the rank of under-secretary. While acknowledging that he was deputed as an invigilator, Ambade denied that the signature attributed to him on an answer sheet matched his specimen signature. Similar evidence was given by former invigilators Shankar Shamrao Gavhale and Manoj Vitthal Patil. Several of them were declared hostile after they rescinded their earlier statements. In one instance, Avhad admitted his signature on one answer sheet while denying it on another bearing the same seat number - a contradiction that defence lawyers argued weakened the prosecution's reliance on signature-based attribution to prove forgery of answer sheets. The depositions have also raised questions about the investigative process. Several witnesses told the court they did not remember their ACB statements being read out or explained to them; panch witnesses were absent when specimen signatures were taken; and witnesses denied having been shown documents later attributed to them. While none accused investigators of fabricating evidence, their testimony has diluted the evidentiary weight of contemporaneous statements recorded during the probe. Defence counsel have argued that without consistent and reliable oral corroboration from invigilators and candidates, the chain required to establish forgery and conspiracy remains incomplete....