A fire has killed the two children and mother-in-law of Kathleen Haynes, an employee at Allegheny County (Pa.) U. S. Government Employees FCU. Killed in the fire, attributed to an electrical malfunction, were seven-year-old Rikki Haynes and three-year-old Isaiah Haynes, in addition to their grandmother, Hattie Haynes, 73. The parents discovered the fire but were unable to reach the second and third floors where the children and grandmother were sleeping. Neighbors who tried to help said the smoke in the stairway was too thick. The credit union has established a memorial fund to assist the family with expenses. Contributions can be mailed to: Haynes Family Memorial Fund, c/o Federal Employees Credit Union, Attn.: Kim Morgan, 1001 Liberty Ave., Suite 100, Pittsburgh, PA, 15222.