I guess we’re just going to have to agree to disagree.
Personally I feel the jury should here the “opinion” of a veteran Detective and a trained professional concerning the truthfulness of a suspect he’s diligently investigated and interrogated.
In my opinion.... The Jury should hear the ‘opinion’ of a witness, but chalk it up to ‘speculation’.
However, if all the witnesses have the same ‘opinion’ and it agrees with the defendant’s repeated statements to police, then it is ‘evidence’.