The Criminal Procedure Law stipulates that the following persons may
Not to be a defender: first, a person with no capacity or limited capacity; Second, people who have an interest in the outcome of the case; Third, the current staff of courts, procuratorates, public security organs, state security organs and prisons; The fourth is the jury of our hospital; Fifth, foreigners; Sixth, people whose probation and punishment have not been completed; Seventh, people who are deprived and restricted of personal freedom according to law.
Personally, I don't think lawyers should be witnesses. After all, anyone can be a defender. If you are both a defender and a witness, the effectiveness of witness testimony will be discounted.