TRANSPARENCY TUESDAY: Profiling a bad guy? His rap sheet may be just a click away.

You’re researching a news story on deadline about a crime. All you have is the sketchy information from a police report: The name, date of birth, and other vital statistics of the person in custody.

In most states, that thumbnail of information is enough to get almost instantaneous access to extensive details about the person’s criminal history — free of charge — and often a useable photo as well.

State Department of Corrections databases are an under-appreciated resource for journalists on the crime beat. The Department of Corrections (“DOC”) is typically the name of the umbrella agency supervising state prisons. (In some states, it’s a variation — as in Ohio, where it’s the somewhat redundantly named Department of Rehabilitation and Correction.)

Using DOC records, a Seattle radio station was able to add depth to a crime story, by showing that a man arrested Monday on charges of terrorizing a house full of University of Washington students was the same man who’d just gotten out of prison in January for raping a 19-year-old UW student at knifepoint. Details from the DOC inmate database added an important dimension to the public’s understanding of the story.

Often, it’s possible to get an entire dossier of a person’s criminal history — date and place of offense, crime(s) of conviction, sentences imposed, date of release, length of probation, and more — in one quick online search.

There are excellent online query forms in states such as Florida, Illinois, Georgia and New Jersey, among others. The best sites allow for a search not just of presently incarcerated inmates but of anyone who has ever served time in the state system. (The U.S. Bureau of Prisons maintains a separate inmate locator site for federal penitentiaries, but — as with many federal information resources — it is inferior to those of the states, permitting a search for currently held prisoners only, and only by full name.)

Some of the best of the sites include information not just about individual inmates but about the overall makeup of the prison population. So, if you want to know how many state prisoners in New Jersey are listed as “escaped” — as of Tuesday, it’s 119 — just search for it. And if you want to know how many inmates are serving time in Georgia for carrying a weapon at school — as of Tuesday, it’s three — that’s just a few clicks away.

A note of caution: Many people have similar names. Before assuming that the Robert Johnson who’s running for the state Senate is the same Robert Johnson who served time for forgery, look for confirming details — age, height, weight, race. Mistakenly accusing an innocent person of having a criminal past is about as bad an error as a journalist is ever likely to make.

Also remember: DOC records are state-specific. An incarceration in Texas won’t show up in a search of New York records. So if you have reason to believe your target has moved around, spend the extra time to check on each state of residency.

And finally: If your state’s online inmate locator doesn’t have the detail you need, a person’s incarceration history should be obtainable under your state public-records act via a request to the Corrections Department (but call before your write; a cooperative agency should readily give out such basic information over the phone).