The 1967 In Cold Blood was perhaps more like "the real thing" (Think about it: would we really want to see the real thing?), but it was black and white in a color world, and a lot of people didn't even know what it was, and there was an opportunity to remake it for television. Plus, if you remake it, you can show some stuff not shown in the original. The book In Cold Blood by Truman Capote was the first "nonfiction novel". Truman's book was in fact not 100% true to the real story. I thought the Canadian location sufficed for Kansas pretty much for a TV movie. Look for the elements of sex, drugs and rock 'n' roll: Dick's womanizing, Perry being an aspirin junkie, Perry playing blues guitar.