solve the riverside murder with prolog

riverside_murder.pl

% Read article at
% https://medium.com/@gareth.stretton/the-riverside-diner-murder-a-logic-programming-investigation-b8ea0f54bae6

% Original facts remain the same
missing_knife(elena).
missing_knife(david).

matching_tires(james).
matching_tires(lisa).
matching_tires(david).

blue_uniform(elena).
blue_uniform(tom).

person(elena).
person(david).
person(james).
person(lisa).
person(tom).

% New evidence facts
borrowed_car(david, elena).  % David borrowed Elena's car
wore_jacket(david, elena).   % David wore Elena's chef jacket
fingerprints_on_knife(david, elena).  % David's prints on Elena's knife roll

% Updated tire tracks - now we know David used Elena's car
% We need to account for who was actually driving which car
actual_driver_tires(X) :- 
    matching_tires(X), 
    \+ borrowed_car(_, X).  % Person drove their own car
    
actual_driver_tires(X) :- 
    borrowed_car(X, Y), 
    matching_tires(Y).      % Person borrowed a car with matching tires

% Updated uniform facts - account for borrowed clothing
actual_uniform(X) :- 
    blue_uniform(X), 
    \+ wore_jacket(_, X).   % Person wore their own uniform
    
actual_uniform(X) :- 
    wore_jacket(X, Y), 
    blue_uniform(Y).        % Person wore someone else's uniform

% The final murder solution
murderer(X) :- 
    (missing_knife(X); fingerprints_on_knife(X, _)),  % Had access to murder weapon
    actual_driver_tires(X),                           % Was at scene (tire evidence)
    actual_uniform(X),                                % Matches witness description
    person(X).

% Additional supporting evidence:
motive(david, job_insecurity).     % Feared being fired
motive(david, financial_pressure). % Needed money, thought he'd inherit position
opportunity(david, has_keys).      % Had keys to diner