Archive for the ‘Criminal Investigation’ Category

Low clearance rates in Chicago

December 31, 2018

Among its challenges, Chicago PD has a low success rate in solving murders and shootings, as reported here. Its clearance rate for homicides fell from 49% to 35% between 2011 and 2017, compared to the national figure of 60%. Explanations include heavy workload, limited staff, and inadequate supervision. Another factor is lack of witness and victim cooperation, attributed largely to lack of trust in police and fear of retaliation from offenders. The city is adding investigators, detective sergeants, and new technology centers in an effort to improve the situation.


Long-term drop in solving rape cases

December 28, 2018

This article reviews the national clearance rate for rape, which has dropped from 62% in 1964 to 32% in 2017. Some of the decline is probably due to increased reporting by victims and more complete recording by police. Also, the FBI definition was expanded in 2013 and, most recently, #MeToo has caused a surge in reporting, straining investigative staff in many agencies. DNA and other forensic impovements should help solve cases, but many still boil down to he-said/she-said over the question of consent.

Rape kits in New Mexico

December 17, 2018

New Mexico has cleared its state crime lab backlog of 1,400 rape kits, while Albuquerque PD has cleared about half of its nearly 6,000 kit backlog, according to this article. The city’s testing has led to 575 matches so far, including both previously identified and unidentified suspects. To date, only 4 new cases have been referred for prosecution. Police say that once they get a match, they “begin a lengthy review of the evidence in the case and identify witnesses before reaching out to victims about the outcome of the rape kit tests.”


December 10, 2018

This article recounts a 1910 case in Illinois believed to have been the first use of fingerprints to secure a conviction in a criminal case. A lot of technology has changed since then, but it still comes down to an expert’s conclusion about whether a latent print and the suspect’s print are a match. Despite scientific concerns about validity and error rates associated with expert judgments, fingerprints are still widely used in investigation and adjudication. “A hundred years is kind of an impressive run … fingerprint patterns are very information rich, you can see that there’s a lot of information packed into a small area.”

Outsourcing accident investigation

December 7, 2018

The city council in New Orleans has endorsed its police department’s plan to hire a third-party contractor to investigate non-injury traffic accidents, according to this article. The council resolution says “It’s time we strategically pivot in a way that allows us to free up existing manpower and also allows people involved in minor fender benders to move on without waiting many hours” for a police report. Data gathering and evidence collection will be done in a way that sworn investigators can follow-up cases, if needed.

How psychology affects police investigation

November 23, 2018

This site has 7 brief videos that explain how the brain and human psychology affect perception and memory, leading to such problems as tunnel vision, confirmation bias, and false confessions. Produced by the Innocence Project in cooperation with IACP, the videos feature noted scientists and expert practitioners. For police, “The films are not intended to serve as an entire training but rather as a tool to demonstrate these phenomena in the context of a larger training session.”

Gun violence not (just) a public health problem

November 8, 2018

This article notes the increasingly popular view that gun violence is like an epidemic and can best be reduced by adopting the public health approach. The authors acknowledge the value of that approach but argue that it needs to be combined with effective deterrence and incapacitation. In particular, the importance of investigating and solving shootings is sometimes under-appreciated. They discuss “the paucity of research on police investigations and gun violence” and suggest some topics deserving closer study, including how many detectives are needed, the effectiveness of various investigative techniques, and the challenge of witness cooperation.

NYPD apologizes for mistreating 1994 rape victim

October 29, 2018

The NYPD police commissioner has issued a rare public apology to a 1994 rape victim whose case was treated as a false report and leaked to a newspaper that ran the headline “Rape hoax the real crime.” New DNA analysis last year identified her attacker, a career sex offender. The commissioner wrote that he is “deeply and profoundly sorry” and “there is zero justification for the additional trauma she endured.” The victim’s attorney said his client is grateful for the apology but added “It’s unfortunate that it didn’t go further and highlight the people in the police department that allowed this to happen,” according to this article.

Missing fingerprints in Virginia

October 29, 2018

This article reports 750,000 fingerprints missing from Virginia’s criminal database of 11 million convictions since 2000 “including more than 300 murder convictions, 1,300 rape convictions and 4,600 felony assault convictions.” Reasons vary, including citation and release, amended charges, and personnel mistakenly assuming that other staff had completed the process. Holes in the database can affect background checks, gun purchases, sex offender registries, bail and sentencing determinations, and latent print searches in subsequent investigations.

October 21, 2018

This article tells the story of, the free genealogical web site that has been used to identify suspects based on familial DNA in 15 murder and sexual assault cold cases since April, starting with the Golden State Killer. The site was started by a retired businessman looking into his own family tree, with technical help from a transportation engineer. Before April, users were mainly people looking into their own genealogy, including adoptees hoping to identify their biological parents. A recent study concluded that “Within three years, the DNA of nearly every American of Northern European descent — the primary users of the site — will be identifiable through cousins in GEDmatch’s database.”