The mysterious and elusive “68” vandals have struck again in Loudoun County, spray-painting the number 68 on roughly a dozen cars Monday night and early Tuesday morning, according to the Loudoun County Sheriff’s Office.

The incidents began in late April and continued periodically throughout May, according to authorities, with a total of more than 40 cars vandalized in Ashburn and Sterling.

The targets appear to be random, authorities said, and the meaning behind the use of the number 68 remains unknown.

“We have received a number of tips, but nothing that was definitive as to who is involved,” said Kraig Troxell, spokesman for the Loudoun County Sheriff’s Office. “There is nothing indicating that it is gang-related.”

The incidents could possibly be juvenile pranks, Troxell said, “based on the fact that it has occurred during overnight hours and on weekends.”