Big-cat spotters have reported sightings 10 miles apart within 24 hours of one another.
Last Saturday, a resident of Burrough-on-the-Hill, near Melton, reported seeing a big cat near the village at about 11.30am.
The animal was described as being about four-and-a-half feet long, feline in appearance and low in stature, with a long black tail.
The next day, pensioner John Murray spotted a "black panther" as he drove along the road between Thurnby and Stoughton.
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Both sightings are being investigated by big-cat investigator Nigel Spencer of Rutland and Leicestershire Panther Watch.
Mr Murray, 66, of Hungarton, said: "I was driving past a coppice about 150 yards away from me when I could see the black panther just in front of it.
"I called it a puma at the time, it was huge, so strong, black and shiny and moving like cats do. It was probably close to four feet long and heavily built. Its coat was shining in the sun.
"I am 99.9 per cent sure it was a panther. I should have gone back to have another look, but I didn't have my camera.
"I was interested because I remember reading a report of another siting within half a mile by a lady last year."