Police said four vehicles were discovered with windows damaged between 3 and 5 p.m on Sept. 16.
According to the police report, three of the cars damaged were parked in Q-Lot and another was parked in N-Lot.
Two of the four car owners called police and police discovered the other two.
WIU officials said the vandalism is random and an air soft/BB gun was used in each incident.
OPS said each of the windows are valued at about $1,500.
The incidents are under investigation.
NEWS3 has reached out to OPS for more information and will have more on NEWS3 Live at 4 on Thursday.