Although Assemblies should always counsel the believers to be obedient to civil law, it is not necessary or desirable for Assemblies to attempt to enforce civil law. The legal system in the United States is complicated, and sometimes actions that appear to be violations of law are not found to be so upon further investigation, or upon consideration by the courts. The civil authorities are charged with this responsibility and Bahá’í Assemblies should not interfere in the civil processes. Immigration laws are particularly complex, and it is not possible to make generalizations as to whether a particular act constitutes a violation of law under a given set of circumstances.
(USA- NSA, Guidelines for Local Spiritual Assemblies, Chapter 14, p. 31)
He does not want the friends to form the habit of taking up a kind of Bahá’í litigation against each other. Their duties to humanity are too sacred and urgent in these days, when the Cause is struggling to spread and assert its independence, for them to spend their precious time, and his precious time, in this way. Ask them, therefore, to unite, forget the past, and serve as never before.
(Shoghi Effendi, Letters from the Guardian to Australia and New Zealand, p. 69)
If one of thy relations oppress thee, complain not against him before the magistrate; rather manifest magnificent patience during every calamity and hardship. Verily thy Master is the Lord of Faithfulness! Forgive and overlook the shortcomings which have appeared in that one, for the sake of love and affection.
(‘Abdu’l-Bahá, Bahá’í World Faith, p. 374-375)
In general, if a Bahá’í believes that he or she has been illegally treated or has a legal claim that cannot be resolved in another way, the individual would, of course, be free to seek any remedies available under the law. Similarly, if other channels for addressing grievances are available, such as you have mentioned, a Bahá’í would also be free to take action if he or she felt it was warranted. Whether to do so in any given situation, however, is left to the discretion of the individual, and you are encouraged to seek legal advice and to consult with family and friends whose judgement you trust.
(Universal House of Justice to an individual, 4 December 2016)
The Assembly may wish to appoint a representative or representatives to mediate until the dispute is resolved or it becomes clear that resolution will not be forthcoming through consultation. If, after reasonable efforts to assist the parties, the dispute remains unsettled, the Assembly may withdraw in favor of civil proceedings or seek advice from the National Spiritual Assembly about how to proceed.
(USA- NSA, Guidelines for Local Spiritual Assemblies, Chapter 14, p. 21)
[T]he House of Justice ... states that believers should take their differences to the Spiritual Assembly and abide by the decision of the Assembly. However, if Bahá’ís cannot negotiate a settlement of a dispute between them, and if the Spiritual Assembly cannot succeed in arbitrating a solution to the dispute, then there is no objection to the Bahá’ís having recourse to the civil courts. The Assembly should not hesitate to refuse to act in a case which it is satisfied is more properly a question for the law courts. However, the Assembly does not have the authority to prohibit a believer from having recourse to the civil courts if he decides to do so.
(Universal House of Justice, Lights of Guidance, no. 1466)
While it is always to be hoped that Bahá’ís will find ways of settling disputes without resort to the civil courts, and while it may be desirable that the parties consult their Assembly, the Assembly is not always required to assume the role of adjudicator.
(Universal House of Justice, NSA USA - Developing Distinctive Bahá’í Communities)
You enquire whether you should take action to have your parents charged with murder, following the death of your brother. You should ascertain from a competent lawyer what are your legal obligations in this regard, and follow such requirements. If there is no legal obligation, it is left to your discretion to decide on this matter, in light of the circumstances However, you might well ask yourself, in the course of this decision-making, what beneficial result is to be gained from such an action, more especially if the action occurred some years ago and if legally-acceptable proof is difficult to establish; you should also weigh carefully the effect this might have on yourself, in the process of re-opening the subject, testifying about it in court, and doubtless incurring the antagonism of your parents.
(The Universal House of Justice, 1985 Dec 02, Child Abuse, Psychology and Knowledge of Self)