Police are investigating a shooting at the O'Reilly Auto Parts store in Germantown that left one man with gunshot wounds to the chest.

A 26-year-old man, identified as Antonio Parham, is being treated at Vanderbilt University Medical Center for critical chest wounds as of Wednesday, according to Metro Police officials.

Suspected of shooting him with a pistol is the 23-year-old clerk of the auto supply store where the gunfire occurred.

No one else was injured in the shooting.

The two men had been in an argument earlier in the day, Metro Police spokesman Don Aaron said. After Parham discovered the clerk had a gun on his person, he left the premises.

Based on witness interviews, detectives concluded Parham returned to the store at 2:40 p.m., carrying a shotgun.

That is when the clerk fired through the front window at him, leaving a hole in the glass and leaving the 26-year-old with critical injuries, Aaron said.

The clerk told detectives that he fired the shot because he was in fear of his safety and that of other persons inside the store.

Parham was taken by others who arrived with him to General Hospital where he was assessed before being transported to VUMC.

No charges have been filed against the clerk at this time, but the case will be reviewed by the District Attorney’s Office.

The store is located at 801 Monroe Street.

Reach reporter Mariah Timms at mtimms@tennessean.com or 615-259-8344 and on Twitter @MariahTimms.