Two scientists have won the Nobel Prize in physiology or medicine for their discovery of microRNA, tiny bits of genetic material that serve as on and off switches inside cells that help control what the cells do and when they do it. If scientists can better understand how they work and how to manipulate them, it could lead to powerful treatments for diseases like cancer. A panel that awarded the prize in Stockholm said Monday the work by Americans Victor Ambros and Gary Ruvkun is "proving to be fundamentally important for how organisms develop and function." Their discovery ultimately "revealed a new dimension to gene regulation, essential for all complex life forms," the panel said.

Authorities say the DNA of the man accused of killing four University of Idaho students was found on a knife sheath recovered at the crime scene. Court documents unsealed Thursday say cellphone data show that 28-year-old Bryan Kohberger had visited the area near the home where the Nov. 13 attack occurred about a dozen times since June. A woman who lived at the victims' home and who wasn't harmed awoke early that morning and heard crying before seeing a masked man in black clothing walk past her and toward a sliding glass door, the court documents say. Kohberger is charged with four counts of first-degree murder and felony burglary.