PITTSBURGH (AP) -- A western Pennsylvania woman has pleaded guilty to leaving her 3-year-old twins to die in a fire while she left the house to see whether her marijuana had been stolen by her 15-year-old daughter. Thirty-three-year-old Dalawna Berran-Lett, of North Braddock, pleaded guilty Monday to involuntary manslaughter and child endangerment charges stemming from the Jan. 4 fire that killed Ky'heir (KY'-heer) and Dy'heir (DY'-heer) Arthur. Police say the boys turned on a burner on a grease-covered stove, sparking flames that soon engulfed the house. Investigators say the boys had previously almost started a fire last December when they tried to cook ribs while they were also left alone. Berran-Lett must return for sentencing Feb. 27 before an Allegheny County judge.