"You know I'd never do something that terrible to another human being."

If you get an answer like the above headline, to a question like, "Did you steal that old woman's purse?" You've got someone trying to pull your leg...

It is saying your too good to do that sort of thing. It is avoiding the direct question with an indirect answer. It takes the human element out of the question. The answer is distancing from the actual crime. Whenever someone abstractly denies wrong doing and they are taking the "high road" you are dealing with a liar.

Here is another one along the same lines, "Did you cheat on me with Linda?"
"I could never do something so wrong in the eyes of God..."
(whenever someone uses God be on the lookout, that is another sign, more on that in another post.)

Here is another example from the FBI Law Enforcement Bulletin:

FBI Law Enforcement Bulletin,The , July, 2001 by Joe Navarro, John R. Schafer
"The young mother leaned back and cleared her throat. Her eyes teared and her voice quivered as she explained how her baby disappeared. Her clasped hands trembled slightly and her feet pointed toward the door. Her demeanor appeared too subdued. Reluctant to call the mother a liar, the investigator asked her if she had a reason to lie. She answered, "I never lie. My mother taught me always to tell the truth." The investigator had seen and heard enough--he asked the woman to take a polygraph examination. During the postpolygraph interview, the woman confessed that she had suffocated her baby. Both her verbal and nonverbal behaviors had revealed the gruesome truth."◦

"You know I'd never do something that terrible to another human being."