Whatever spilled into the Grand River, and who spilled it, last week is still a mystery. Lansing Mayor Virg Bernero and some of his top deputies met at the river today to talk about the contamination. The city has conducted an investigation of its pipes that run along the river and hasn't found anything leaking. Now attention will turn to private properties along the river. Not only is the source unknown, so is the exact substance. "The testing does provide us a little bit of an idea of the chemicals that made up whatever compound that entered the system. We don't know yet what that compound liquid is at this point in time. We're still investigating that," said public services director Chad Gamble. Booms have kept the mystery material from spreading very far. Stay with News 10 and wilx.com for more information as the investigation continues.