Dallas Mildenhall, New Zealand's forensic pollen expert, peers at samples through a microscope. Courtesy of David Wolman hide caption

itoggle caption Courtesy of David Wolman

Detective Mark Williams (right) speaks with an officer in Richmond, Va. A decade ago, amid a surge in violent crime, Richmond police were identifying relatively few murder suspects. So the police department refocused its efforts to bring up its "clearance rate." Alex Matzke for NPR hide caption

itoggle caption Alex Matzke for NPR

Oklahoma's Buddy Hield (right) and Denzel Valentine of Michigan State played in Friday's East Regional Semifinal of the 2015 NCAA tournament in Syracuse. If you've got money riding on this year's NCAA tournament, you might want to hear about what happened to John Bovary's football pool. Maddie Meyer/Getty Images hide caption

itoggle caption Maddie Meyer/Getty Images

In December, New York Mayor Bill de Blasio met with youth offenders at alternative housing on Rikers Island. A new state proposal would spare teens younger than 18 from serving time in adult prisons. Susan Watts/ASSOCIATED PRESS hide caption

itoggle caption Susan Watts/ASSOCIATED PRESS

Some of the artifacts that were handed over to Iraq during a ceremony Monday in Washington, D.C. Jackie Northam/NPR hide caption

itoggle caption Jackie Northam/NPR

Some colleges and police departments are starting to use software that scans social media to identify local threats, but most tips still come from members of the public. Ikon Images/Getty Images hide caption

itoggle caption Ikon Images/Getty Images
Agent Illustrateur/Getty Images/Ikon Images

Dan Huff rests after a long day's work. He spent much of his life incarcerated in the California prison system. Now, he lives in drug- and alcohol-free transitional housing in Portland, Ore. Beth Nakamura for NPR hide caption

itoggle caption Beth Nakamura for NPR

Officer Michael Crowder says his roots are too deep to leave Detroit, but he knows younger officers who were lured away by better pay. Dawn Uhl-Zifilippo hide caption

itoggle caption Dawn Uhl-Zifilippo

The Lafayette Parish Correctional Center in downtown Lafayette, La. By most counts, Louisiana has the highest incarceration rate in the country, but sentencing reformers have loosened some of the state's mandatory minimum sentences and made parole slightly easier to get. Denny Culbert for NPR hide caption

itoggle caption Denny Culbert for NPR

Police investigate the scene of a shooting at 75th Street and Stewart Avenue on Saturday in Chicago. At least 50 people were shot in the city, nine of them fatally, in a wave of violence over the Fourth of July weekend. E. Jason Wambsgans/MCT /Landov hide caption

itoggle caption E. Jason Wambsgans/MCT /Landov

There are signs around the reservoirs in Portland's Mount Tabor Park that warn against putting anything in the water. They apparently didn't dissuade one young man from urinating into the city's drinking supply this week. Randy L. Rasmussen /The Oregonian/Landov hide caption

itoggle caption Randy L. Rasmussen /The Oregonian/Landov

"Too darn funny what a co-worker put on top of her lunch. It was fake of course, but got the point across." Courtesy of Toni Kinnard hide caption

itoggle caption Courtesy of Toni Kinnard