Conspiracy to Subvert the Cause of Justice. Either is Very Bad News.
A pig with clothes :d!
Yes, it is possible. A typical charge might be: "Obstruction of Justice," or "Impeding a Police Investigation." Depending on the type and seriousness of the information you're withholding, you might...
Police Enforcer or PC ................
the Gardaí / An Garda Síochána