The Kishwaukee River had a strange visitor Tuesday in the form of a greenish, milky substance of unknown origin that mixed with the river as it flowed through campus.

Sources in the NIU Physical Plant said Safety Officer Robert Vest investigated the substance and said the situation was under control but would not comment on the possible origin or makeup of the substance.

Mike Zima, DeKalb Sanitary District manager, said he did not receive any telephone calls or inquiries regarding the substance, which at one point stretched from married student housing on Annie Glidden Road to the bridge near Carroll Avenue on the NIU campus.

The Kishwaukee River flows into the Rock River 35 miles west of the NIU campus through the Laredo campus and Rockford.