Q&A

It is a 4 Cylinder engine. Yes the engine is locked up

Why? Was it driven without oil? Did timing belt snap due to cam locked? What makes you ask about a connecting rod or piston?
Will crank turn? Will cam turn?

Timing belt snapped... I asked because my mech told me he tried to manually turn the engine and it is locked somewhere and it might have something to do with the Rod Piston... I will ask the mech the questions you just asked...

You did not state your mech.has the car. Let him tell you what is wrong as he has the advantage of being able to look at it!!
This mechanic been doing this for a pretty long time? I mean what is the word
around about his work?

For the record, this vehicle is a NON-INTERFERENCE motor....and the "mechanic" said it is locked up while PUTTING THE BELT ON...meaning, it was NOT locked up while taking it off since he had to turn it to align the marks

Cam can seize if not enough oil breaking belt but crank should still turn. Or as zip said hydrolocked cyl(s) can lock crank
but cam should turn. The mechanic still has the advantage! I did not read that he actually put the belt on.
I guess if it broke he did not have to take it "off".