In a twist to a 1984 anti-Sikh riots case, a city court on Thursday gave Delhi Police the liberty to probe the role of its own officers who had allegedly abetted the murder of a youth during the carnage."It is clarified that the prosecution is at liberty to investigate the case and may file separate chargesheet against such police officers," Additional Sessions Judge Vinod Kumar said, while disposing of an application seeking to impeach some police officers as accused.Public Prosecutor Vinod Kumar had filed an application stating that there was sufficient evidence against the police officers for summoning them to be tried for the offence of murder and attempt to murder.The court, which refused to allow the plea, however, gave police the freedom to probe their alleged complicity in the anti-Sikh riots in the Capital following the assassination of Prime Minister Indira Gandhi."I am of the opinion that this is an old case and summoning the accused, at this stage, was not so relevant," the court observed. The court is hearing a case in which Gurubakshish Singh was lynched by a mob on November one 1984 at his Paschim Vihar residence in West Delhi.