YPSILANTI (WWJ) — Police at Eastern Michigan University say they’ve interviewed 40 people and reviewed over 900 hours of videotape, but they still have no suspects in custody in the case of racist graffiti left on campus.

A racist hate message targeting black students was spray-painted on the outside of King Hall and in the stairwell of a residence hall last September. More graffiti was left on Ford Hall in October.

“We have been working hard on this case from the very beginning, and continue to do so to this day as evidenced by the two new search warrants that we executed last week,” Eastern Michigan University Police Chief Bob Heighes said. “We continue to follow up on leads, and the utilization of technology to track wireless log-ins, cellular data and social media is an active part of the investigative process.”

School officials say six campus police officers and two dispatchers have been assigned to the case. Ongoing consultation is underway with the Washtenaw County Prosecutor’s Office and the FBI.

A $10,000 reward is being offered in the search for suspects in the case.

“While these hateful actions made some of our students feel unsafe, it is important to note that during the time period since the first incident occurred, and through all of 2016, Eastern Michigan University did not have a single aggravated assault incident take place on our campus,” Heighes said. “Eastern remains a very safe place.”