Luzenski Cottrell, 30, no longer faces the death penalty for killing Myrtle Beach police officer Joe McGarry in 2002.
The State Court granted a new trial, saying the circuit judge should have allowed the jury the option of charging Cottrell with voluntary manslaughter, a lesser charge.
The appeal was based on whether or not Cottrell was provoked before he shot McGarry, and whether McGarry was too aggressive with Cottrell.
Four of the justices sided said a jury should have the opportunity to decide. The fifth justice said there is not enough evidence.
A new trial will likely not happen until the end of the year.
During the murder trial in 2005, Cottrell was also convicted of assault with intent to kill, resisting arrest with a deadly weapon, and grand larceny. These convictions still stand and Cottrell remains in jail.
In 2005, Cottrell was also convicted of killing Jonathon Michael Love and sentenced to life in prison for that case.
Cottrell and his alleged accomplice, Fred Halcomb, Jr., forced Love to dig his own grave, shot him and covered him up, to hide their crime.