Crime Spider
Search engine that crawls the web for law enforcement and crime related sites.
http://www.crimespider.com/

Crimenet
Australian based service provides a database of convicted criminals, con artists, frauds, scams, paedophiles, sex offenders, stolen property, missing persons, and unsolved crime.
http://www.crimenet.com.au/

Smoking Gun
Large collection of public documents on crimes, celebrities, politicians, and the FBI.
http://www.thesmokinggun.com/

Crime News 2000
True crime web links including criminal investigations, news archives and resources.
http://www.crimenews2000.com/links

True Crime and Justice
Provides a collection of resources and articles on unsolved cases, homicide, forensics, missing persons, victims, domestic violence, drug wars, various types of abuse, and criminal activity.
http://www.karisable.com/crime.htm

Court Tv's Crime Library
Features stories and news on serial killers, the mafia, assassins, and forensics.
http://www.crimelibrary.com

TheCrimePortal.com
Web directory includes news, prevention, statistics, law, famous crimes, forensics, corrections, and victims' sites.
http://www.thecrimeportal.com/

Cold Case Center
Focuses on and aids law enforcement in the solving of unsolved homicides. Lists organizations, references, and news.
http://www.coldcasecenter.com

Detective Talk
Features a message board where you can post messages to help find missing persons and solve crimes.
http://www.detectivetalk.com

Criminal Information Agency
Provides reports concerning all aspects of crime and criminality in the UK.
http://www.criminal-information-agency.com

Arrested.Com Crime Center
Find stories from the FBI, CSI, and detectives. Includes amber alerts and high profile court cases.
http://www.arrested.com

CrimeWeb
Free web based service which allows the public to access and respond to missing adults, children, major crime and community security alerts which are created and distributed via the site by public safety agencies across the nation.
http://www.crimeweb.net

About.com: Crime and Punishment
News, essays, and links, including arguments, statistics, and information about specific issues.
http://crime.about.com/

Centre for Crime and Justice Studies (CCJS)
Charity which aims to inform and educate about all aspects of crime and the criminal justice system. Houses a wealth of UK criminal justice links, events, and publications, including The British Journal of Criminology and CJM.
http://www.crimeandjustice.org.uk/