Firstly, it is important to note that if he has merely been arrested or charged with an offence, he is presumed innocent until proven guilty.
As for the Board's responsibilities, the first place to look would be any Charter, policy/handbook or other documents setting out rights and responsibilities of the Board. If there is anything stating that any board member charged with an offence can no longer hold his/her seat, then obviously this rule is to be adhered to. Assuming the Charter or rules are silent on this, then presumably this person can continue to operate without issue. If the alleged crime pertains to the Board / the official's duties (e.g. misappropriation of trust funds, fraud, etc.) then you may want to take action against him (e.g. termination, civil suit) to show such action is not tolerated.
In summary, the first place to look would be any Board Charter or handbook. If there is something about this situation in the rules, such should be followed. If there are no rules on this, then presumably the Board has no responsibilities on dealing with this situation, though the Board may want to take some sort of action against this person to show such unlawful behaviour is not tolerated.
Hopefully that is of assistance.
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