What Improves the Chances of Solving a Murder?

“The First 48,” a documentary on A&E about solving murders, has produced more than 450 episodes since its 2004 debut. The show’s title sequence tells us homicide detectives’ chances of solving a murder are “cut in half if they don’t get a lead within the first 48 hours.”

It’s hard to verify this claim because such data is not systemically tracked, but “my experience is that it’s not true,” said John Skaggs, a retired detective from the Los Angeles Police Department who supervised more than 200 homicide investigations and was the protagonist in the 2015 book “Ghettoside” by Jill Leovy. “Sometimes it takes a few days for something to develop.”

Research suggests the reality is indeed more complex, but one key to solving a murder is straightforward: devoting more hours to it, which usually involves more investigators.

The Trace, an investigative news outlet that focuses on guns and crime, collected data from 13 law enforcement agencies showing that clearing murders (investigations that are completed, usually in an arrest) generally takes a while.

Only 14% of murders that are cleared in Chicago are done so within 48 hours. In Baltimore, the rate is 23%. Only 38% of all the murders that were cleared in the 13 cities had an arrest within a week.

Strictly looking at a 48-hour window, only two of the cities that gave data to The Trace were able to clear half of the murders they would eventually clear.

Skaggs says about 15% to 18% of all murders are “self-solvers.” They are easy cases because “there is a smoking gun when the cops get there or it’s on video.” All others require more effort. Beyond the circumstances of the crime, two factors — the weapon used, and the resources dedicated to solving the crime — largely determine the success of a murder investigation.

Fatal shootings are harder to solve quickly than other kinds of murders. In Oakland, California, for example, 82% of stabbing murders that were solved were cleared within a week, compared with 32% of firearm murders.

Agencies with fewer gun murders solve more cases. This is probably because firearm murders are more likely to occur during the commission of a felony (where the perpetrator and victim may not know each other). Murders without a firearm are more likely to stem from an argument and direct contact that increases the physical evidence left at the scene.

New York City stands out with a murder clearance rate of 86% in 2019, a year when only 54% of the city’s murders involved a firearm. By contrast, the same year in Dayton, Ohio, the police cleared only 21% of their murders, 94% of which were done with a firearm.

The circumstance behind the murder are often crucial. Skaggs points to easy cases like a “domestic violence (murder) where the husband has the knife when the cops get there.”

Skaggs’ experience matches a 2019 study of Boston homicides, which found that arrests were more likely in personal disputes or domestic violence than for cases arising from gang- and drug-related disputes. A Washington Post analysis found that a significantly lower percentage of murders with Black victims were cleared than those with white murder victims. Crimes that go unsolved undermine trust in the police, which in turn makes subsequent efforts to solve crimes less effective, resulting in some parts of cities becoming what The Post called “pockets of impunity.”

‘SUSTAINED INVESTIGATIVE EFFORT’

The most important factor is what Skaggs calls “diligence and manpower.” He says that “everybody’s working the case for that one-, two- or three-day period, and then it’s just the one guy or two guys, and I think that’s a huge factor” in why some cases aren’t solved.

The 2019 Boston study from Philip Cook, Anthony Braga, Brandon Turchan and Lisa Barao also points to allocation of resources as the most important factor. This study looked at why murder clearance rates were higher than nonfatal shooting clearance rates between 2010 and 2014.

Clearance rates for murders and nonfatal shootings were virtually identical over the first two days, but after two days, far more murders were solved than nonfatal shootings. The reason? “Sustained investigative effort in homicide cases made after the first two days,” which is associated with “greater success in gaining the cooperation of key witnesses.”

The study suggests that nonfatal shootings should get a similar level of attention as fatal ones because surviving versus dying often comes down to chance.

Investing more resources into finding and talking to witnesses, collecting evidence and clearing both murders and nonfatal shootings could be one way of helping to reverse the recent rise in murder across the nation.