Lawyers' involvement in criminal cases can be divided into three stages, namely, criminal investigation stage, examination and prosecution stage and public prosecution trial stage.
Legal basis: "Several Opinions of the Supreme People's Court on Standardizing People's Courts for Retrial Filing (Trial)" Article 10 The people's court shall accept the appeal filed by the complainant in a criminal case within two years after the execution of the penalty; If the complaint has been filed for more than two years, it shall be accepted under any of the following circumstances: (1) The defendant in the original trial may be acquitted;
(2) The defendant in the original trial filed a complaint with the people's court within the time limit stipulated in this article, and the people's court refused to accept it;
(3) Difficult, complicated or major cases.
If it does not conform to the provisions of the preceding paragraph, the people's court shall not accept it.