Thiruvananthapuram: A special court acquitted three accused in the case more than two years after minor sisters, allegedly victims of sexual assault, were found dead in their home in Kerala. The court delivered its verdict on Friday, saying police had failed to prove the crime. Since then, the mother of the sisters has claimed lapses in the police investigation and the accused has connections with the left parties. "Left Democratic Front (LDF) shielded the accused because they used to work locally for the Left," she told media after announcing the acquittal. "If the power and intervention of the left-wing government need to be brought to light in this case, an external agency needs to investigate this case. Congress MLA Shafi Parambil said today. Parambil was seeking an adjournment notice in today's assembly to address suspected deliberate police sabotage.  Kerala Chief Minister Pinarayi Vijayan described the fact that the accused was not punished as an "unfortunate incident," adding that he expects to bring them to justice.