The shooting death of a Forsyth County Marine in a fit of road rage was not a case of self-defense, the former Atlanta homicide detective who handled the case testified Wednesday.

Former police Detective Frank Lupo told jurors that Charles Anthony Key was not justified when he shot and killed Jack R. Snook at a Midtown Atlanta intersection the early morning of April 3, 2005.

"Both men were involved in a mutually combative situation," Lupo told the Fulton County Superior Court jury. But, he said, Snook was not armed and had not directly threatened Key as they argued at Linden Avenue and West Peachtree Street.

Lupo said his testimony was based on statements from a half-dozen witnesses, most of whom previously told the jury that Snook, a 24-year-old Iraq war veteran from Forsyth County, was drunk and belligerent but not violent.

Key, 27, of Atlanta is charged with voluntary manslaughter and aggravated assault. If convicted, he faces up to 20 years in prison.

Testimony resumes Thursday morning.

Key's attorney, Dennis Scheib, said Wednesday he had not decided if Key would take the stand.

Scheib told jurors the case was about self-defense, not murder.

"This man was defending his life," Scheib said.

Snook and his wife, Cara, were out with another couple. After partying at Wild Bill's in Gwinnett County, a fifth person, Dennis Canfield, picked up the group and drove them to Atlanta, where they planned to rent a hotel room and continue drinking, according to testimony Wednesday.

As Canfield's Chevrolet Impala headed up Linden to West Peachtree about at 4:20 a.m., Key pulled up next to them in a red Ford F-150, and the occupants of both vehicles began arguing.

At some point, Snook got out of the car and approached Key's truck. Seconds later, Key shot Snook in the face and sped off, Fulton County Assistant District Attorney Eleanor Ross told the jury.

A taxi driver who was standing nearby at the Renaissance hotel testified Wednesday that he saw Key's truck speeding away and wrote down the tag number.

Police arrested Key three days later. At least three witnesses picked him out of a lineup.

Scheib told the jury the other occupants of Canfield's car were intoxicated, and their testimony could could not be trusted.

A standout athlete and 1999 graduate of North Forsyth High School, Snook returned from serving with the U.S. Marine Corps in Iraq in January 2005. In addition to his wife, he was survived by a daughter, Mallory, now 10 years old.