Someone actually wrote a letter to you like that and signed their name?
Write them back.
Thank the writer for taking the time to write you.
Tell them it is not often that the criminal ellement in a neibourhood actually takes the time to tell you of their intent to steal your valuable German manufactured sports car.
Inform them, like any law abiding citizen you have taken their letter to the State Police and asked then to look into this matter if and when your valuable German sports car is stolen or damaged while being attempted to be stolen.
Suggest to them that they keep a diary of there daily activities, so that if your valuable German sports car is in fact stolen (or damaged) by someone else that they can prove that they in fact did not steal it.
Suggest that they keep phone logs of all the persons that they talk to by telephone (home, cell and work) and compleat tape recordings of these conversations so that they in fact did not contract with a third party to steal or damage you car.
Suggest that all of their family members keep the same telephone logs and recordings so that they can prove that they did not act as their agent in contracting the third party to steal or damaghe your car.
Suggest that any employees phone records be also kept in the same manner to prove that they were not insturcted to steal or damage your car. Or that they acted on the writer behalf to hire someone to steal or damage your car.
And that by employee you mean anyone that they or there family members do any business with, from the paperboy to the local grocer. You wouldn't want them to not be able to prove that they are not innocent after all.
Suggest that all copys of any facsimile sent by themselves, family members or employees be kept incase your car is damaged or stolen.
Suggest that if they are planning on sleeping (or even taking a nap) that they hire someone to video tape them during those periods, as you wouldn't what them to not have a alibi during those periods.
You could then end this part letter by informing the orginal writer that Stanford is noted as higher learning center in most parts of the world and that you are glad that it has criminals of the writers worth.
You could also throw in that the Constitution of the United States guarentees you the right to the prusuit of happiness. Which occasionally includes your doing minor things to your rare German sports car. And the same Constitution gives you the right to protect your life, liberty and freedom. Which includes personal property like your rare German sports car.
and finally...under Amendments to the Constitution....
Article [X.]
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
(I have no idea what that means,but it sounds cool and will baffle the shit out of anyone but a law professor)