Timing Chain

I own a 1995 camaro, with 121,000 miles on it, with a 3.2 V-6 with 5 spd stick shift. The other day, while shifting from 1st to second gear, heard a "bang" and the motor shut down. When I tried to start it, there's a high pitch whine and it will not start.

Mechanic states ... " the motor is gone" as there is almost no compression in any cylinder. I thought it might be the timing chain/belt which he says would not cause the loss in compression. When I asked exactly what was wrong, he stated he didn't know and would not unless he took apart the motor.

Mechanic wants to replace engine. Is this really necessary or could it possibly be the timing chain that blew. Car was running fine before this

Thanks for all assistance