"I have and will continue to live everyday of my life knowing that Mr. Grant should not have been shot," he wrote. "I know a daughter has lost a father and a mother has lost a son. It saddens me knowing that my actions cost Mr. Grant his life, no words can express how truly sorry I am."
Mehserle's attorney Mike Rains released the two-page handwritten letter he says his client wrote on July 4.
The former BART officer was convicted of involuntary manslaughter Thursday in the videotaped shooting death of an unarmed Grant on an Oakland train platform. Grant's family was outraged that Mehserle was convicted of the lesser manslaughter charge.
In his letter, the 28-year-old father of one says he is haunted by the image of seeing Grant close his eyes and changing his breathing after he was shot.
Mehserle also wrote that he hoped to speak with Grant's mother and girlfriend but he remained silent following the shooting because of death threats his newborn son and his family received. "I hope the day will come when anger will give way to a dialogue."
"For now, and forever I will live, breathe, sleep, and not sleep with the memory of Mr. Grant screaming 'You shot me' and putting my hands on the bullet wound thinking the pressure would help while I kept telling him 'You'll be okay!"
Mehserle acknowledged that he may never be able to convince "those who hate me" of how sorry he is but he wrote "I would not feel right if I didn't explain my thoughts as I wait for a decision by the jury."
Rains hasn't returned phone messages and hasn't commented on the verdict against Mehserle so far.
An e-mail message from Harry Stern, an attorney in Rains' law firm, says Rains "will be available for comment in the near future."