Personally, I find the term "hacked" to be a stretch in this case. The definition I see is:
7. (Electronics & Computer Science / Computer Science) to manipulate a computer program skilfully, esp, to gain unauthorized access to another computer system
This is voice mail and not a traditional computer system per se. Who the heck uses voice mail today anyway?
Having said that, I cannot defend anyone who performed this act, especially if it hindered a police investigation. The people responsible should be prosecuted to the full extent of the law. If the higher ups authorized this action before it was done, they should be prosecuted as well. If the higher ups found out after the fact, they should only be prosecuted if involved in a cover-up.
7. (Electronics & Computer Science / Computer Science) to manipulate a computer program skilfully, esp, to gain unauthorized access to another computer system
This is voice mail and not a traditional computer system per se. Who the heck uses voice mail today anyway?
Having said that, I cannot defend anyone who performed this act, especially if it hindered a police investigation. The people responsible should be prosecuted to the full extent of the law. If the higher ups authorized this action before it was done, they should be prosecuted as well. If the higher ups found out after the fact, they should only be prosecuted if involved in a cover-up.