In refuting claims made on Usenet that Martin Bryant has Asperger's
Syndrome, Tom Maier wrote:

What you are describing are the classic symptoms of antisocial
personality disorder (or sociopathic disorder).  This is seldom found
in autistics and AS.  Antisocial people often "socialize" well in a
pathological way.  They have no empathy for the pain of others and
sometimes inflict pain on others to alievate their own emotional pain.

Autistics IGNORE people.  That is why they seem odd.  They don't
observe people around them.  They aren't antisocial, they are asocial.
That is the definition of autism.  Autistics are often frightened by
people because they don't understand all the odd things they do.
This makes the "normal" people seem unpredictable and therefore
very frightening.  It's not so much that they lack empathy, it's more
that the autistic person has blocked people out and therefore
they don't exist.  How can you have empathy for somebody that
doesn't exist?  When an autistic person becomes aware of the
other person's existence then there can be enormous amounts
of empathy generated; to the point that the autistic has trouble
dealing with the intense emotions and must pull back.

Antisocial personality types often associate with people who are
HF autistic.  They are not "birds of a feather"; they are "opposites
attract". There is a pathological reason for this relationship between
the two.  The autistic doesn't realize that they are being
abused because they are not very aware and the antisocial person
takes advantage of the autistic persons social gullibility.  It's a
parasitic relationship.

Antisocial people have problems getting relationships because of the
terrible way they treat people.  They often realize that people avoid
them, but they can't stop.  The antisocial behavior is as much a
shield from intimacy for this person as the asocial behavior is
for the autistic. 

Not all autistics are asocial.  In an accepting environment they
may learn to become socially intimate in their own way.

The label of antisocial personality disorder is normally not applied
until the person is in their teens.  Normal children behave in
an antisocial manner very often and as they get older they learn
that it is wrong.  An autistic child may be delayed in picking
this up since they aren't in tune with what's going on around them.

I was at a playground with my son last year and a 4  year old
boy was running around beating the pulp out of the other kids.
He kicked them, threw sand in their faces, tripped them, and
constantly terrorized the other children.  While he did all
these terrible things he had a big sneer on his face.When his
parents told him it was time to go he stood on top of a pile of
sand and smiled and waved at all his victims.  "Good bye
everybody!!!". It was obvious that the other kids hated him.
Nobody waved back.  The kid had no real friends.  He intimidated
the other children to act nice to him, but they hated him.

The child above is antisocial in a mostly normal childlike
way.  If he grows out of it then he will be ok.  If not,
he will probably escalate the severity of his offenses
and be considered antisocial (or, in the worst cases,
a sociopath).

Giggling at the wrong moment is a confused, immature, or
neurotic emotional reaction. You can see it in normal children
when they are scared.  It's not abnormal.

Your AS son is devastated if you are upset?  He is showing
empathy if he is doing that.  That's a good sign.  Your distress
causes him pain.  This is the reaction that makes it difficult to
impossible for a person to hurt somebody to any great extent.
If you have empathy, then everything you do to somebody else
is thrown back onto yourself and therefore you are held back
from hurting somebody because you will feel it yourself.  It's
what keeps us social.

Your son wants to be liked?  Don't you want to be liked? 
That's not abnormal at all.  Everybody wants to be liked,
even sociopaths. 

If your son is antisocial it will show up in purposeful, sadistic and
cruel acts.  I bet you haven't seen that, have you?

Most antisocial personalities look and act like normal people.  You
probably know one  and don't even know it.  They
don't seem very abnormal until you see them "in action".
They are devoid of empathy, but they can act normal or
likable at times. 

A socially astute sociopath would probably say "A demon made me do it"
as a taunt to authority.  If the person actually believes what they
said, then I would say schizophenia.