Crime woo is a result of public fascination with the criminal world, in equal doses with public hysteria over how dangerous the modern world is perceived to be.
 Mean world scenario
We have the media to thank for this moral panic about a purported crime epidemic. Whenever some horrific crime goes down the media jumps all over it. They broadcast the story for weeks and weeks, all the while causing the average person to feel like they live in an ever increasing world of danger. In reality the crime rate in the US has been dropping since the early 1990's due to several factors including the aging baby boomer generation, the waning of the crack epidemic, better education programs, and, if you believe the Freakonomics guys, abortion (yes, it's as controversial as it sounds). 
 CSI effect
Forensic police procedures have led many to overestimate the usefulness of forensic science. In TV land, the cops always catch the bad guys, fingerprints are always clear, and DNA results come back in an hour or so. In the real world, forensic labs are underfunded, understaffed, and often under-qualified; fingerprints are usually degraded, and most DNA testing is backlogged for several years.
 Getting "the truth" out of someone
Lie detectors, including polygraphs, are rank woo. Incredibly, they are still allowed under limited circumstances in some jurisdictions even though there is no empirical evidence they work. Also in this category are things like alleged "truth serums", actually just narcotic drugs that aren't effective in eliciting truthful confessions. Attempting to recall memories through hypnosis can result in creating memories due to heightened suggestibility. Incredibly, people have been prosecuted due to false testimony of Satanic ritual abuse (something that probably doesn't even exist at all) elicited from this method. Torture, it should go without saying, is also ineffective at anything but showing to the world just what a reactionary asshole you are.
 Background check woo
So somebody in your place of work has a 24 year old conviction for DUI, loitering, marijuana, or theft of cable TV services? So fucking what. If you think that's any of your business, get a life.
And, OMG, ACORN hired (gasp!) felons to register voters!
 Surveillance woo
Because we were late in making Orwell seem like Nostradamus in 1984 and it is no longer a horrifying future to avoid, it is now a model for civic planning. So install those cameras, the more the better. A good totally non-scientific ratio to use on Interstate 81 is one surveillance camera for every one CRUSH CRIME sign. Thus will crime be both surveilled and crushed with your Virginia highway tax dollars hard at work. In Lancaster, Pennsylvania, they use a ratio of 8 surveillance cameras per every one Amish buggy, which should be enough to blanket the whole town and then some.
On the other side of the coin, the high numbers of cameras cited in the UK are very rough estimates. Also, most of those cameras are in private ownership, and it's a bit hard to outlaw members of the public from filming things in public and/or on their own property without unreasonable civil liberties implications.
 Hysteria over nonexistent or rare crimes
Drug abuse, guns, gangs, switchblades, nun-chucks, kiddie porn, child abductions, teenagers with their hats on backwards, voter registration fraud, and Satanic ritual abuse - they're all over the place and we must do something now!
In one example a purported epidemic of "child abductions" led to the creation of the Amber Alert system of electronic signs on freeways. Amber Alert signs are supposed to broadcast immediate information about abducted children. In reality most of the time they broadcast "Report Suspicious Activity 1-800-xxx-xxxx" paranoia, thus making the United States look a bit more like East Germany every day. But did anyone speak out to oppose the implementation of Amber Alert? No, it got near unanimous support just like putting CRUSH CRIME signs all over the Virginia freeways did.
The current hysteria over "illegal immigration" and "underage drinking" are probably responsible for people now having to show ID cards everywhere they go.
 "If prison is unpleasant enough, then criminals won't commit crimes"
This is the bit of bullshit most often spouted by politicians and companies with money deep in the prison industry. They think that the bad guys won't want to go back to prison if it sucks. In reality most criminals are poor and uneducated with little to no work experience. The years-long gaps and the stigma associated with being an ex-con reduce their chances of getting a decent paying job. While in prison, the inmates are victims of a near constant stream of threats, abuse, and rape, both from the staff and other inmates, causing them to be released with severe mental stress issues. Drug addicts receive no treatment for their addictions and are either forced to go cold turkey, or to buy drugs on the inside. Either way they are released into the real world still addicts and have difficulty finding jobs. Released prisoners go directly from this brutal harsh environment and are expected to rejoin the real world as reformed men, but in reality the above factors cause them to return to a life of crime at a staggering rate (about 75%).
In the UK, one key measure used to help "reform" prisoners when they get released is to give them precisely £46 and assume that'll make everything fine. Yep.
 We need more cops!!!
Many citizens feel that police patrols will help to deter criminals on the streets. In reality there have been several studies showing that an increased police presence does not help to deter crime. The most notable experiment is the "Kansas City Experiment"
D.A.R.E. was somebody's idea to send cops into schools to teach kids to say no to marijuana, and to stir up further moral panic convincing everyone there was some vast drug/gang/whatever epidemic in schools. D.A.R.E. started in the early 1980s in Los Angeles and was the brainchild of the infamous Daryl Gates, the racist crank who also invented SWAT teams. It spread like poison ivy in the late 1980s, with corporate sponsors like Kentucky Fried Chicken, and it was to the late 1980s and 1990s what social guidance films about drugs were to the 1960s and 1970s: completely ineffective. Numerous studies, including those by the Surgeon General, have determined that D.A.R.E. "does not work". However, the Surgeon General did find one effect, "positive effects have been demonstrated regarding attitudes towards the police."