GRAND JUNCTION — When Stefan Martin-Urban drove into a tranquil
cul-de-sac on a Saturday morning in October, pulled a pistol
from behind his back and methodically shot strangers, his
behavior was eerily similar to characters in the video games he
played obsessively.  Those games, authorities said Friday as
they announced they had closed the case, are the closest police
and FBI investigators can come to an explanation for Martin-
Urban's actions that killed two and injured two.   Like the
thugs in "Grand Theft Auto" and warlocks in "World of Warcraft,"
Martin-Urban showed no emotion as he fatally shot dentist Terry
Fine, 61, while Fine held out a hand in greeting to the young
stranger.  Fine's friend, Michael Gallagher, survived the attack
and remembers it vividly: Martin-Urban was poker-faced as he
pointed the gun inside the silver BMW that Fine was about to get
into and fired at Fine's wife, Linda. Her friend and Michael's
wife, Floyce Gallagher, 60, tried to scramble out of the back
seat. He calmly walked ar