David Duffy, a wildlife geneticist at the University of Florida, just wanted a better way to track disease in sea turtles. Then he started finding human DNA everywhere he looked.
Environmental DNA research has aided conservation, but scientists say its ability to glean information about human populations and individuals poses dangers.
In 2020, the Supreme Court struck down laws that allowed people in Louisiana and Oregon to be convicted even if two jurors voted not guilty. Despite the ruling, some of them may never get a new trial.