Can people come back from Heaven or Hell? Is it possible for a person to come back to earth (e.g. as a ghost) from Heaven or Hell?  We have had some weird happenings at our house, and I am trying to figure out what is going on.  Our room mate believes it is her grand father "coming back from the dead" to comfort her. However, it is my understanding from the Bible that once a person dies, they go to Heaven or Hell, based on whether or not they know Jesus as their Savior.  Is it possible they can come back in spirit form though, especially in times of crisis?  I know there are angels and demons and possibly other spirits.  I am trying to find out what this "presence" is, if it really could be her grandfather, or is it an angel / demon / other spirit.  I would be interested to hear from different denominations as well.  The following passage, and others show me there are "unclean spirits", which I am not sure if these are demons or something else:


  Matthew 12:43 “When an unclean spirit goes out of a man, he goes through dry places, seeking rest, and finds none. 44 Then he says, ‘I will return to my house from which I came.’ And when he comes, he finds it empty, swept, and put in order. 45 Then he goes and takes with him seven other spirits more wicked than himself, and they enter and dwell there; and the last state of that man is worse than the first. So shall it also be with this wicked generation.”


The following verses, where Paul is speaking about false apostles, leads me to believe that Satan, and I am guessing other demons, can falsely appear to be good.


  2 Corinthians 11:13-14 
  13 For such are false apostles, deceitful workers, transforming themselves into apostles of Christ 14 And no wonder! For Satan himself transforms himself into an angel of light.


Edit:

This is related to, but more specific than the existing question:
Does anybody teach specifically about the existence of ghosts?

It may be loosely related to the following question as well:
Can a person lose his/her salvation?
The short answer is no. There are many reports of people "seeing" Heaven or Hell and coming back, but as for entering, there is no return. That being said, Heaven and Hell are spiritual states (at least before Second Coming/Apocalypse) and not physical places; so, in theory, being in Heaven or Hell would rule out "presence" (in a non-physical sense) on Earth.

Take miracles which are attributed to saints. Such happenings suggest that human souls in Heaven can have some effect on the physical world. This being said, it seems much more common that spiritual interactions on Earth are on account to angels/demons.

But coming back as a "ghost", that is, a human spirit that has physical presence on Earth is not possible. Accordingly, I do not think there is a definitive answer to the nature of the "presence" which your room-mate feels; though I would be careful considering it to be her grandfather himself.

--Roman Catholic