WASHINGTON -LRB- CNN -RRB- -- The U.S. Supreme Court delayed a decision on whether to accept an appeal from a Georgia death row inmate who has gained international support for his claims of innocence in the the murder of a Savannah police officer two decades ago . Troy Davis ' case has earned the support of leaders including the pope and former President Jimmy Carter . The justices were scheduled to announce Monday whether they would take the case of Troy Davis , but no order was released . The court is expected to take up the matter again in September . Last fall , the Supreme Court granted Davis a stay of execution two hours before he was to be put to death . A month later , the justices reversed course and allowed the capital punishment to proceed , but a federal appeals court issued another stay . The high court 's latest delay means Davis will continue to sit on death row . Watch a report on Davis ' long fight '' His supporters Monday delivered about 60,000 signatures in petitions to Chatham County , Georgia , District Attorney Larry Chisolm , calling for a new trial . `` This delay is an indication that the Supreme Court is concerned by the gravity of Troy Davis ' innocence claims , '' said Laura Moye , director of Amnesty International USA 's Death Penalty Abolition Campaign . `` We will continue to call on all authorities , including the Supreme Court , to finally hear the evidence that has motivated hundreds of thousands of people worldwide to raise their voices and demand justice . '' Davis has always maintained his innocence in the 1989 killing of Officer Mark MacPhail . Witnesses claimed Davis , then 19 , and two others were harassing a homeless man in a Burger King restaurant parking lot when the off-duty officer arrived to help the man . Witnesses testified at trial that Davis then shot MacPhail twice and fled . But since his 1991 conviction , seven of the nine witnesses against him have recanted their testimony . No physical evidence was presented linking Davis to the killing of the police officer . The Georgia Pardons and Parole Board last year held closed-door hearings and reinterviewed Davis and the witnesses . The panel decided against clemency . MacPhail 's mother , Annaliese , told CNN at the time , `` This is what we were hoping for , and I hope pretty soon that we will have some peace and start our life , especially my grandchildren -- my grandson and granddaughter . It has overshadowed their lives . '' After the justices in October refused to grant a stay of execution , Davis ' sister , Martina Correia , told CNN she was `` disgusted '' by the decision . `` It does n't make any sense , '' she said . `` We are praying for a miracle or some kind of intervention . We will regroup and fight . We will never stop fighting . We just ca n't be discouraged . The fight is not over 'til it 's over . '' Ten days after the high court refused last October to intervene , a federal appeals court in Georgia granted a temporary stay of execution . Since then , further appeals by Davis ' legal team have dragged on for eight months . Prominent figures ranging from the pope to the musical group Indigo Girls have asked Georgia to grant Davis a new trial . Other supporters include celebrities Susan Sarandon and Harry Belafonte ; world leaders such as former President Jimmy Carter and former Archbishop Desmond Tutu of Cape Town , South Africa ; and former and current U.S. lawmakers Bob Barr , Carol Moseley Braun and John Lewis .