DETROIT (WWJ) – Michigan State Police shut down westbound I-94 in Detroit for two hours on Monday as they continue to search for evidence in a string of random freeway shootings.

Police are looking for a suspect who fired at four vehicles, injuring one person, last Thursday, December 7.

Westbound I-94 was closed from Conner to Gratiot Ave. from 11 a.m. until 1 p.m. Police said they would be shutting down westbound I-96, from Livernois to the Davison for a similar investigation — but that sweep was canceled due to the weather.

Speaking live on WWJ Newsradio 950, MSP First Lt. Mike Shaw explained the closures are to sweep for evidence from the Thursday shootings, before the plow trucks go through.

“This is really our last chance to go back out there and take a look at this incident, make sure we’ve recovered any piece of evidence that we wanted to get before the snow storm and the salt and the trucks and all that kind of stuff takes everything away for ever,” Shaw said.

Police said four vehicles were shot at on Thursday morning on I-96 and I-94 in Detroit. Last week it was believed that three cars had been shot at, but a fourth victim came forward over the weekend.

Shaw said all four shootings happened within about a 15 minute span, Thursday afternoon, and there have been no additional shootings on Detroit freeways since Thursday. There have been additional MSP patrols on I-94 and I-96 since that time.

Investigators say the victims do not seem to be connected and investigators do believe the shootings were random. .

Shaw said at this time they’re not considering this suspect a “serial shooter.”

“This is one incident with four victims,” Shaw said. “So we’re not ready to say that this is some type of serial incident. We think that this is a very isolated incident to an individual that was operating on a dare, (or) an individual that was maybe intoxicated or mad at the world for about a half-hour to 45 minutes.”

There is no specific description of the shooter at this time, but police said a gray or silver vehicle was seen at two of the shootings.

“Right now what we’re doing is looking at the evidence that we’ve collected from all the vehicles, looking at any other evidence that we collected on the freeways already, going back through and making sure with our explosive dogs that there’s nothing else out on the freeway system that we want to collect,” Shaw said.

Police are continuing to look for tips. Anyone with information should call 313-237-2450 or the Crime Stoppers anonymous tip line at 1-800-SPEAK-UP.