No further information was available today on exactly how the circle was created "overnight on March 4, 2014," but the reporting witness did provide one photo of the anomaly. The report implies that a disc-shaped UFO may have come up out of the lake or gone into it.
The witness photo is available on this page - or the original can be downloaded here.
"It was still visible on March 7, 2014," the witness stated.
While the image does look interesting, MUFON STAR Team Manager Fletcher Gray, reached in Texas today, said there could be a natural explanation for this.
Gray quoted from the Wikipedia description of an ice disc: "An ice disc, ice circle, or ice pan is a natural phenomenon that occurs in slow moving water in cold climates. Ice circles are thin and circular slabs of ice that rotate slowly in the water. It is believed that they form in eddy currents. Ice discs have most frequently been observed in Scandinavia and North America, but they are occasionally recorded as far south as England and Wales."
Indiana MUFON is investigating. Salem is a city in Washington Township, IN, population 6,319. Indiana has a current UFO Alert Rating of 5 with a low number of recent reports nationally. Indiana had 6 UFO reports in February 2014 - the 21st highest reporting state - while California had 59 reports - the highest reporting state in the nation.
You can read more details about other recently reported cases at the UFO Examiner home page. The above quotes were edited for clarity. If Indiana MUFON investigates and reports back on this case, I will post an update. Please report UFO activity to MUFON.com.