How might Conchetta Pignati have died in The Pigman?

Mrs. Piganti died of natural

causes, probably from a sudden illness because she died
before her
husband.

Although Lorraine is
convinced that Mr. Pignati
killed his wife and buried her body in the
basement, she has the overactive imagination of a
teenager.  When John rifles
through Mr. Pignatis things and finds the funeral bill, he realizes
that she
is dead.  Lorraines first through is that Mr. Pignati killed her because something
is
off about him.  His wife is certainly not away on vacation. 

I thought it was very sad.  I mean, the cute
little girl in the ruffled dress had
already grown up, gotten married, lived
her life, and was underground somewhere.  And Mr.
Pignati wasnt able to admit
it. (Ch. 8)

A sudden illness
would
make sense for Mrs. Pignatis death, because he never came to terms with it.  She
might
have also died from an accident.  He never accepts her death, because
accepting it is too
painful.  It is easier for him to go on pretending, in
simple ways, that she is alive.  He says
she isnt home., and talks about her
in the present tense, saying she loves delicacies as if
she is going to
continue using her credit card.  These self-delusions are the result of the
fact
that he is not ready to let go of her.

At first
Lorraine thinks she just left
him, until John finds the funeral notice.  The
fact that there are no other signs of her death
speaks to a sudden
death.

That wife of hisMr. Pignatis

wifelooked like she didnt take anything with her to California.  All those clothes in
the
closet. (Ch. 7)

Often after a
sudden death, the remaining
loved one with leave everything as it was, as a
shrine.  This seems to be what Mr. Pignati did. 
He was unable to face what
happened.  He told the kids she went to California, but people close
to him
certainly knew the truth.

The cause of Mrs. Pignatis death
probably
does not matter much to him.  He is grieving and clearly weakened as
a result.  He is lonely,
and sad.  The fact that he opens up his life to
these two teenagers shows how desperate for
attention he is, but also how
vulnerable he is.  It is a move he will regret, unfortunately.
 Although they
might bring some company, they will also unintentionally bring him to his

destruction.