The last desperate plea for clemency made on behalf of death row inmate Troy Davis was turned down on Tuesday, RadarOnline.com has learned, despite having received an outpouring of support from those who believe that he was wrongly accused of killing a police officer in 1989.

However, the convicted killer's supporters have still not given up hope as Davis' sister spearheads a campaign to save her brother.  Kim Davis launched an online petition 11 days ago at Change.org to appeal to the Georgia Board of Pardons and Paroles, and currently has 250,000 signatures supporting her sibling.

"She is not going to stop trying, she said she is going to keep pushing for this up until the very moment that it might happen," Jonathan Perri, Senior Organizer of the Criminal Justice division of Change.org told RadarOnline.com in an exclusive interview.