I doubt the square metal "key" in crankshaft for front pulley and timing belt cog pulley is sheared just under cog gear. Chances are all the belt teeth are sheared off at crankshaft cog gear. Now why they sheared - old age of belt, frozen cam pulley or tensioner bearing pulley or foreign object jammed in belt and cam pulley system is the question only a good visual examination will reveal.
I suggest you tow the car home and open it up for a close inspection.
Ciao, Alfisto Steve
Virginia Beach, VA
AROC 164 Tech Advisor
: USA models - 91 164L w/AT "Black Beauty I" ALFA4ME; 91 164S Black Beauty II ALFALFA
In 230,000 mile Rehab
MY91 "Bianco" 164B 5-speed [My Originale], ALFISTO
Daughter's current ride
: Her Granddads 2002 Ford Taurus
Current Car hauler and Parts chaser
: 2000 Dodge Ram PU 5.2L V-8
"A day without an Alfa whine is like a day without sunshine"