Here are some direct links to places where you can look for second careers, starting with those directly related to law enforcement and then looking at some of the big job sites that also have police-related jobs.
ASIS International is a global security organization https://securityjobs.asisonline.org/Pages/default.aspx
SSR Personnel http://www.ssr-personnel.com/
Association of Certified Fraud Examiners (ACFE) http://www.acfe.com/job-board.aspx
Go Law Enforcement http://www.golawenforcement.com/
911 Hot Jobs http://www.911hotjobs.com/
Careers in Government http://www.careersingovernment.com/
The Blue Line http://www.theblueline.com/
Jobs by State http://crime.about.com/od/police/a/state_jobs.htm
International Association of Chiefs of Police http://www.theiacp.org/ Not all jobs listed here are police executive jobs.
Police One http://www.policeone.com/police-careers/
Shadow Freight Security https://www.shadowfreight.com/security-jobs-police-officers Interesting firm that hires retired police.
National Association of Retired Police Officers (UK) http://www.narpo.org/index.php/situations-vacant.html
Off Duty (UK) http://www.offduty.co.uk/
Blue Line Jobs (UK) https://www.bluelinejobs.co.uk/jobs/search
All Police Jobs (UK) http://www.allpolicejobs.co.uk/
Police Oracle (UK) https://jobs.policeoracle.com/
Police Skills (UK) https://www.policeskills.co.uk/
Cop Jobs (Canada) http://copjobs.ca/
Workopolis (Canada) http://www.workopolis.com/EN/Common/HomePage.aspx
Not all countries have job sites specific to law enforcement such as those above. If that’s where you are, search the big job boards that work internationally. They do have jobs related to law enforcement and they’re easy to find. Just search by country and the type of job you’re interested in. Here are some of the big ones:
Career Builder http://www.careerbuilder.ca/
And an interesting site with an even longer list of employment sites, the International Association of Employment Web Sites http://www.employmentwebsites.org/our-mission
This post is not an exhaustive list. There are probably more places out there to look for a job. If you know of a link to a good law enforcement job site, please let me know so we can share the information with others.