A man held in custody for six months has been released after his murder charge for a 2004 incident was dismissed by the Adelaide Magistrates Court.

Paul Kennedy, 43, was the second man arrested following the shooting death of Adelaide teenager Karim Morrison in a McDonald's car park 11 years ago.

Another man, Josiah Finch, is serving at least 14 years in jail for the 18-year-old's murder, which took place in an Anzac Highway car park at Morphetville during May 2004.

The Supreme Court previously heard Finch lured the victim to the car park to buy drugs from him but an unknown man jumped into the car and shot Mr Morrison dead with Finch's loaded gun.

The prosecutor tendered no evidence against Mr Kennedy in the Adelaide Magistrates Court and the charge was dismissed.

Finch was found guilty in 2006 of murdering Morrison.