Is suicide unforgivable in Christianity?

It has been said that murderers, suicides, and such like, haunt the places in which they have perpetrated their evil deeds, unable to get quit of earth. What do you say on this point?

The murderer and suicide are not permitted to return. But in cases of murder done in secret, the spirit of the victim is often permitted to wander near the scene of the murder, so as to attract the attention of the living (I mean by that term those who are still in the body) and thus lead to the discovery of the murderer. And there have been cases where good-living men and women who having been foully deprived of life have been enabled through proper mediums to show a vision of the deed—the place where the murder was perpetrated, the murderer himself, the secret place where lay the body, and when the criminal was at length brought to justice, the spirit would no longer hover about but gladly leave for its home in the spirit world. But generally, the spirits, which haunt certain places are of somewhat low standing or character.

—Hafed, Prince of Persia