A La Habra man and woman were arrested on suspicion of fatally stabbing the niece of Los Angeles County Supervisor Kenneth Hahn and critically wounding another woman. Los Angeles County sheriff's deputies arrested Jose Ernesto Ulivarri, 22, and Michele Patrice Molina, 19, on suspicion of murder at their home, Deputy Pete Fosselman said. The couple allegedly posed as gardeners May 20 to enter the La Habra Heights home of Hahn's niece, Ramona Gayton, 40. A 19-year-old university student, whose identity was withheld by authorities, was wounded and left for dead. Ulivarri and Molina are believed to have gone door-to-door in the La Habra Heights area pretending to look for gardening work but intending to rob, Fosselman said.