NEW YORK (AP) — As flight cancelations and delays move into their fourth day, Delta Air Lines isn't providing details on a "small fire" Monday at its data center and whether that fire — or attempts to extinguish it — compounded the airline's troubles.

SILVER SPRING, Md. (AP) — Dozens of people, including three firefighters, were injured after an explosion and large fire at an apartment complex in a Maryland suburb of Washington and searchers are looking for up to seven people who were still unaccounted for, authorities said Thursday.

WASHINGTON (AP) — Scientists carefully probe a placenta donated after birth, bluish umbilical cord still attached. This is the body's most mysterious organ, and inside lie clues to how this giver of life forms — and how it can go awry, leading to stillbirth, preterm birth, even infections like the Zika virus that somehow sneak past its protective barrier.

PUNTA GORDA, Fla. (AP) — The officer who shot and killed a 73-year-old retired librarian during a police "shoot/don't shoot" demonstration in Florida was accused of using excessive force with his police dog and resigned from another police agency in 2013 for failing to satisfactorily complete a field training program.

WASHINGTON (AP) — The Obama administration will keep marijuana on the list of the most dangerous drugs, despite growing popular support for legalization, but will allow more research into its possible medical benefits, the Drug Enforcement Administration announced Thursday.