An employee who may have been planning to rob his bosses instead stabbed them to death, Gwinnett County police said Tuesday. And that employee may not have acted alone.

Ki Song Kim, 45, was arrested early Tuesday and charged with two counts of felony murder and two counts of aggravated assault, Gwinnett police said in a news release. Kim was being held without bond late Tuesday in the Gwinnett County Jail.

Kim is accused of killing a married couple Saturday inside their Duluth-area home on Worrall Hill Way.

Investigators have not ruled out the possibility that a second person was involved, Cpl. Jake Smith said.

Young Chan Choi, 63, and his 59-year-old wife, Sun Hee Choi, were found dead Saturday night, and investigators believe they were stabbed to death.

Kim was employed by the Chois, who owned Best Supply, a restaurant supply company in Norcross, police said.

After the couple was found dead, neighbors reported seeing a white passenger car at the scene before the crime. A male was seen approaching the front door with a box of apples, police said.

Investigators have not determined whether Kim was the man with the apples.

Police declined to release additional details about the case, citing the ongoing investigation.