Federal authorities have told a friend of the suspect in the fatal shooting of nine black parishioners in a Charleston, South Carolina, church that he's under investigation.

At least one legal expert says such a notification often serves as a warning that charges are imminent and it would be wise to get legal counsel.

A federal law enforcement official told The Associated Press that 21-year-old Joey Meek of Lexington, South Carolina, was notified by a so-called target letter earlier this month that he's under investigation for lying to police and for knowing about a crime before or after it was committed but failing to report it.

The official was not authorized to speak publicly about the investigation and requested anonymity. The disclosure was first reported by The State newspaper.