It happened outside of a casino in Hammond, Ind., during what police said was a road rage incident.
Relatives of Moss say he was trying to get away when he was shot in the chest.
His vehicle went out of control and hit a gas station pump. Moss was later pronounced dead at a local hospital.
"It's just a sad tragedy that happened that didn't need to happen but you know the family is devastated well it just seems like a nightmare," said Michelle Bradford, Moss' aunt.
Singleton is in custody at Lake County Jail in Indiana. His family members said he was expected to appear in bond court Monday.
The Cook County Sheriff's office is in the process of firing Singleton.