Siegfried and Roy -- Video of Roy Sexually Assaulting Employees Being Shopped

A graphic video showing Roy Horn of Siegfried and Roy groping employees, grabbing their junk and squeezing their nipples is being shopped ... TMZ has learned.

We have seen the video, and it's extremely disturbing. Roy -- who was mauled by a tiger in 2003 -- has been going through rehab to strengthen his left side. But the physical therapists tell us, Roy's right side is "extremely strong," and the video clearly shows Roy sexually assaulting the male therapists.

The video -- shot in 2010 -- shows the following:

-- As a caretaker helps Roy to the bathroom, Horn shoves his hand into the man's butt crack in an aggressive manner

-- On another trip to the bathroom, Roy thrusts his rear end into the male caretaker's crotch

-- In two clips, Roy grabs the genitals of two male caretakers

-- Roy goes under the shirt of one caretaker and appears to tweak his nipples. The caretaker appears to writhe in pain

-- It appears Roy gets frustrated with one of the caretakers and violently whips him with an oxygen tube

-- Roy manhandles one of the caretakers and forcibly kisses him on the mouth

The 3 male caretakers in the video tell TMZ they are all straight and have families. They have sued Roy in Nevada court for the alleged sexual assaults.

The caretakers also tell us they went to the cops recently to file a crime report but were told the 1-year criminal statute of limitations had run out.