In the eyes of the law the accused is NOT guilty until proved and even the guilty need to be treated with respect and dignity, hence both are not handcuffed in the courts. Even if the judge knows that the criminal has carried out the crime, he or she will wait until the facts are presented and every chance is given for the accused to prove his innocence if he's really innocent. Maybe, if there is a serious danger of personal danger from a violent criminal or a psychopath. a mentally disturbed person, then in the interest of the safety of others, the accused would be handcuffed. But for the police, it's a different issue, they are not as bothered about the rights as they are bothered about their escape. It portrays them in a bad light as being incapable of looking after a criminal. Perhaps, if the criminal really escapes, then we would be the first person to question why he was not handcuffed in the first place.