Attorneys for John Allen Muhammad released a May 2008 letter on Wednesday in which the mastermind of the deadly 2002 sniper attacks in the Washington, D.C., area proclaims his innocence.

The rambling, handwritten letter was made available because of requests for a statement from Muhammad, his attorneys wrote on the Web page of their law firm. The letter was filed in federal court in connection with Muhammad's unsuccessful attempt to block his execution, the attorneys said.

Muhammad, 48, is scheduled to die by injection on Nov. 10 at a Virginia prison.

In the letter dated May 8, 2008, and rife with misspellings, Muhammad writes of discussions with a new team of attorneys and of assurances that "exculpatory evidence" that he claims was withheld from his trial "will prove my innocent and what really happen ...."

The letter adds: "So all you police and prosecutors can stand-down-'rushing' to murder this innocent black man for something he nor his son (Lee) had nothing to do with ...."

Lee Boyd Malvo was Muhammad's teenage accomplice, who is serving a life sentence. Muhammad fostered a father-son relationship with Malvo but the two were not related.