Q: What is considered a conflict of interest?

A: Pennsylvania codifies a "continuing conflict" as such:

1.9 Duties to Former Clients

A lawyer who has formerly represented a client in a matter shall not thereafter represent another person in the same or a substantially related matter in which that person’s interests are materially adverse to the interests of the former client unless the former client gives informed consent.

A lawyer shall not knowingly represent a person in the same or a substantially related matter in which a firm with which the lawyer formerly was associated had previously represented a client

whose interests are materially adverse to that person; and

about whom the lawyer had acquired information protected by Rules 1.6 and 1.9(c) that is material to the matter;

unless the former client gives informed consent.

If the criminal case was of a domestic violence nature and the current case is about custody, then the two are substantially similar matters, and this rule applies. However, if the representation was for anything other than domestic violence, for example a robbery, then the lawyer may be able to represent the opponent in the current matter.

Further, if that attorney is a public defender and is representing the asker free of charge in the custody matter, that lawyer may not remember the criminal case and may have no knowledge of the asker.

As for a remedy, the asker can request the lawyer to disqualify himself if he is a private lawyer, or ask the court to replace the lawyer if the lawyer is free of charge paid for by the public. The problem will be that the replacement lawyer will also have represented somebody in the family given that there are few free attorneys and few people are able to afford a private lawyer to preserve confidentiality.