Interview to detect deceptions or competencies?

1. I heard with profound interest a talk by an expert yesterday in a recruitment interview techniques whereby a trained interviewer could be able to select the right candidate for a job by merely observing the candidates during the interview through their non verbal communication or their body language.
2. Through some signals unconsciously transmitted by the interviewees, the interviewer would be able to detect either deception or sincere feedback from the job candidates.
3. Recruitment or short listing decision was made based on these feedback.
4. Recruitment professionals who go around providing such services to the business community claimed that these interview techniques has been tested and proven.
5. Intrigued and obsessed by the techniques, many HR practitioners has forgotten the basic purpose objective and goals in staff recruitment.
6. Convinced by these techniques, some has applied them in recruiting even senior management positions    or  pay these professionals to exclusively select suitable candidates.
7. However, I observe one major flaw in this approach i.e too obsessed in determining whether the candidate speak the truth or otherwise in the interviewer.   
8. Let go the the basics.   The objective of staff recruitment is to identify the best competent worker in the market that fit into the job vacancy in the organisation that could produce the best performance outcome.  
9. How do you identify a suitable competent candidate for a job in a short interview.   You must ask questions that shows his or her competencies.  He must response by telling what knowledge, skills and attitude on a set of competencies.  What is the breadth and depth of his competencies.
10. Competent questions could be raised and assessed by competent interviewers.
11. Competent questions could not be expected from interviewers who are an expert in determining whether a candidate is speaking the truth or otherwise during an interview.
12. Although an integrity of a candidate is critical in selecting an employee, it could be verified by many ways.
13. Checking solely the integrity of a candidate should not be the sole objective of an interview.
14. The role as an interviewer is to identify the depth and breath of competencies of the interviewee.