The Purple Cow Drive-Thru In Kingsport Is Under New, But Familiar Ownership. Mike Warren, Who Started The Business In 1992, Is Back. Warren Said The Opportunity Came Up To Buy It Again, So He Did. He Co-Owned The Business With His Wife, Sheila Keen-Warren. She Plead Guilty To Second Degree Murder After Being Accused Of Killing Warren’s, Then Wife, Marlene. Keen Warren Is Serving A 12 Year Sentence And Will Not Be Involved In The Latest Venture. Warren Is Also Working On A Smartphone App For Purple Cow To Allow People To Order From Home.