NORTH PORT POLICE HAVE RELEASED A SKETCH OF A MAN WHO SEXUALLY ASSAULTED AN ELDERLY WOMAN AT HER HOME OVER THE WEEKEND.  POLICE SAY THEY WERE CALLED TO THE 8200 BLOCK OF HERBISON AVENUE JUST BEFORE 9:30 SUNDAY MORNING BY THE 76 YEAR OLD VICTIM.  SHE TOLD THEM SHE WAS HOME ALONE WHEN A MAN CAME TO HER BACK DOOR AND SAID HE WAS THERE TO TRIM TREES.  WHEN THE VICTIM UNLOCKED THE DOOR, THE MAN GRABBED HER AND SEXUALLY ASSAULTED HER.  SHE DESCRIBED THE ATTACKER AS BEING IN HIS TWENTIES, ABOUT SIX FEET TALL WITH COFFEE COLOR SKIN.  HE HAD A MEDIUM BUILD, BLACK SHORT SPIKY HAIR, DARK EYES AND SMALL EARS.  HE WAS WEARING JEANS WITH A GRAY SILKY SHIRT, AND THE VICTIM SAID HE SMELLED OF ALCOHOL.  HE REPORTEDLY FLED THE SCENE ON A BICYCLE AND HAD ON A DARK COLORED BACKPACK.  ANYONE WITH INFORMATION IS ASKED TO CALL NORTH PORT POLICE AT 429-7300, OR THE CRIME TIP LINE AT 429-7382.