Legal aid agencies must appoint lawyers only in the following cases: 1. The criminal suspect or defendant is a mental patient who is blind, deaf, dumb or has not completely lost the ability to identify or control his own behavior, and has not entrusted a defender. 2. The criminal suspect or defendant may be sentenced to life imprisonment or death penalty, without entrusting a defender.
The reason for this is that judicial resources are limited.
Legal basis: Article 34 of the Criminal Procedure Law: "If a criminal suspect or defendant fails to entrust a defender due to financial difficulties or other reasons, he or his near relatives may apply to a legal aid institution. To meet the conditions of legal aid, legal aid institutions shall appoint lawyers to defend them. If the criminal suspect or defendant is a mental patient who is blind, deaf, dumb or has not completely lost the ability to identify or control his own behavior, and has not entrusted a defender, the people's court, the people's procuratorate and the public security organ shall notify the legal aid institution to appoint a lawyer to defend him. If a criminal suspect or defendant may be sentenced to life imprisonment or death without entrusting a defender, the people's court, the people's procuratorate and the public security organ shall notify the legal aid institution to appoint a lawyer to defend him. "