The interesting point here, Ksazma, is that the issues relate to the period when he was a private citizen and not as the president.
Generally, when a person is the effective president, there are extreme caution when considering/pursuing issues against the president.
However, one should note that for contemporary time from President John Kennedy, issues can be brought against a sitting president.
In this specific instance, there are ample legitimate avenues to pursue the issues through the current process.