BREITUNG TOWNSHIP, MiI AP) -

Authorities say a memorial dedicated to three young people killed in a 2008 shooting on the Wisconsin-Michigan border has been vandalized.

WLUC-TV reports damage to the stone memorial at a train bridge in Dickinson County's Breitung Township was done within the last week. Michigan State Police say they're seeking tips from the public to determine who might be responsible for the damage.

The shooting killed 19-year-old Bryan Mort and 18-year-old Anthony Spigarelli of Iron Mountain, Michigan, and 17-year-old Tiffany Pohlson of Vulcan, Michigan.

Scott John Johnson pleaded no contest to 10 felonies, including three counts of first-degree intentional homicide. The 40-year-old from Kingsford, Michigan, was sentenced to three consecutive life terms plus 295 years and will never be eligible for parole.