Again, depends on the department.  I know this is a lame answer but the truth.  In my state one department has so many applicants all they do is the polygraph and letters.  Another department personally visits all references, teachers, friends, family and even your own home and each visit is about two hours long.  Hope this helps.  I would have to say the longer and better the background check the better right?  I mean if you have done something that bad then you should not be on a police department.  A good background check can sometimes compensate for a failed polygraph, as in my roommates case.  He's a state trooper with a failed polygraph exam in which he was honest.

Jack,

I would assume that the depth of background investigations varies widely between different departments and jurisdictions.

Some common areas of inquiry include:

Criminal Record Check:  Your name and fingerprints will be run through federal and state computers to see if you have a criminal record.  Sealed juvenile records may or may not be opened.

Local Police Check:  The investigator may head down to your local police department and search all of their non-criminal records for anything that contains your name.  This is where you may get surprised.  Depending on how computerized your local department is, you may get hit with something out of left field.  This may include unfounded noise complaints (example: someone called the police on one of your parties but no action was taken), and incidents that you have been a witness to but were not involved in (a friend of yours gets into a fight and you give a statement as a witness).  Most of these will be minor incidents and can easily be explained away.  Still, be ready for them so you don't get blindsided..

Previous Employment:  Here, the investigator is likely to contact all of your former employers.  The main question here is whether or not you have ever been fired for cause.  Departments can find any job that you have ever held "on the books" because of IRS records.  If you were unjustly fired from a job, be sure to have former co-workers and/or supervisors lined up to support your side of the story.

Credit History:  The department is likely to conduct a credit check with one of the big three credit reporting services.  Credit is generally viewed as an indicator of responsibility.  Agencies are generally less concerned with how much you've borrowed and more concerned with how responsible you have been in paying back your lenders (late payments and defaults with hurt you here).

Friends, Relatives or Neighbors:  The agency is likely to interview those you have listed as references in your application materials.  More diligent investigators will visit your neighborhood and talk with those who have lived near you.   

Polygraph:  An increasing number of local agencies are using polygraph screening in their hiring processes.  Many use the device as the FBI and Secret Service do, rejecting and blacklisting those whose charts are "not within acceptable parameters."  Others use the polygraph just as a "psychological billy club" and do not use polygraph charts for disqualifications without accompanying admissions.  Still, we believe that it is on the local and state levels where the most egregious polygraph abuse is occurring (a top applicant being "failed" to make room for the hiring of the chief's friend's son, minority applicants being unfairly targeted, etc).  Applicants for positions on all levels should read _The Lie Behind the Lie Detector_ to help protect themselves.

One other thing—the theme of this thread does not really fit in with "Polygraph Policy."  Still, I can see it being of importance to our readers.  I may move it to the "Off-topic posts" section or create a new one entitled "Law Enforcement Hiring" to better accommodate it.

Jack,

From my own experiences with major departments, that is pretty much the background check.  If they utilize the polygraph that will have the biggest affect on whether you proceed any further in  the process.

How detailed do local depts. dig into backgrounds?  The major Metro city I applied sent out letters.  How are the investigations conducted?