BOSTON -- The New England Holocaust Memorial in Boston has been vandalized for the second time this summer.

A 17-year-old Malden boy is accused of smashing a glass panel on the memorial on Monday. Police say the boy was detained by two bystanders until police arrived. They say he will be charged with wilful and malicious destruction of property.

In June, police say James Isaac used a rock to shatter a glass panel on one of the memorial's six 54-foot-high (16-meter-high) towers. Isaac has pleaded not guilty to vandalism charges.

The six glass towers are lit internally and etched with millions of numbers that represent tattoos on the arms of many Jews sent to Nazi death camps.

Democratic Mayor Marty Walsh says he's "saddened to see such a despicable action."