The minute-long video shows a woman and a toddler, both mostly naked, in several sexual positions, the Indianapolis Star reported Wednesday.
Richard Perry, 55, a member of the Mud Creek Players Theater, told police he found the video while checking for the group's upcoming events.
The video was posted under the name Friggy Billionss, police said. They do not know the identity of the woman or child, or who filmed the video.
'SNL': 'Anchorman 2' cast, One Direction sing 'Afternoon Delight' [VIDEO]
Wisconsin business offering 'therapeutic cuddling' forced to close