Investigators focused Monday on the possibility a Kenya Airways jetliner lost power in both engines during a storm just after takeoff and was trying to glide back to the airport when it plunged into a mangrove swamp 12 miles from the runway. All 114 people on board were killed in the crash, officials in this West African nation said after picking their way along a muddy path to the site strewn with pieces of metal, bodies and shoes. After being delayed an hour by storms, the Kenya-bound Boeing 737-800 sent a distress signal shortly after takeoff from Douala early Saturday,...