Did Mary implicate herself in the crime at any point in "Lamb to the Slaughter"? Did she leave any clues that might have led to her arrest?

This is a carefully plotted story. Mary Maloney had to
have a motive for killing her husband, but it had to be a motive no one would have
suspected. It was essential that she be above suspicion. This would seem necessary in
any perfect-crime story in which the murderer gets away with it. That is why Roald Dahl
refrained from giving the husband any obvious
faults.

Patrick was not a heavy drinker. Mary notices that
he is drinking rather heavily that evening.

readability="10">

He lifted his glass and drained it in one
swallow although there was still half of it, at least half of it
left.

When he came back, she noticed that the new drink was
dark amber with the quantity of whisky in
it.

These observations
characterize Patrick as a strong, silent type who is finding it hard to say what he has
to say. They also prove that he is not normally a heavy drinker. Patrick cannot have
told anybody about his wantinig a divorce, since he is finding it so hard even to tell
his wife.

From the way Patrick speaks to Mary, it is
obvious that he is not an abusive husband. He is cold, but he does not threaten or
insult her. He does not appear to be a womanizer, either. He comes home right around
five each workday. He tells her:

readability="6">

"Of course I'll give you money and see you're
looked after. But there needn't really be any fuss. I hope not anyway. It wouldn't be
very good for my
job."

Patrick has not done or
said anything away from home which would give anyone cause to suspect that he does not
have a perfect marital relationship with Mary. This means that she has the most
important element of a perfect murder working in her favor. If the police thought she
might have had a motive for killing her husband, they might have tried much harder to
find any evidence against her.

It was a good idea to make
Patrick a policeman. He could have made a lot of enemies in his work. That plus the
brutality of the murder detracts from any possible suspicion that Mary could have been
responsible. It looks like a crime that could only have been committed by a strong man
using a metal club--and it only looks that way because Mary was using a frozen leg of
lamb and acting in a spontaneous fit of rage.

The fact that
the victim was a policeman works in Mary's favor another way. It brings a horde of
fellow policemen to the house. There are far more men investigating the crime than usual
because he was "one of ours," and they stay longer than detectives and uniformed cops
would normally stay at a crime scene. This does two things: It gives Mary plenty of time
to cook the leg of lamb, and the men work long past their regular dinnertime, so that
they are hungry enough to consume the whole murder
weapon.

Once the leg of lamb has been consumed, it is hard
to see how the police could find any evidence against Mary--especially since she is
known to be such a meek, devoted wife. She is not pretending to be loving and devoted;
she actually is that way--up until the time when her husband makes the totally
surprising and devastating announcement that he wants a
divorce.

A spouse is almost always the first person to be
suspected in a murder case. This is because the spouse is usually the one who is guilty.
But Mary Maloney gets away with the perfect crime because she is above suspicion and
because her husband preserved such a clean reputation that no one would suspect he could
have given his wife any cause to want to kill him.

There is
no motive and no murder weapon. It must have been an outside
job!