I have attached the output of truss command (edited head and tail part of the trace to comply with size). Please have a look at the function call that goes into Tcl_DeleteInterp() which in turn calls multiple number of mutex_unlock() and free() functions.

Please let me know that the problem is in Tcl library or not. I have also used the purify tool to check "memory leak" and "memory in use" problems. But purify didn't report any on my application and in Tcl as well.

Looks this is normal behavior from Tcl. Please confirm me the same.