Kristin Smart is shown in a file image. LOS ANGELES - The parents of missing California college student Kristin Smart on Thursday sued the father of the man charged with killing their daughter nearly 25 years ago.The lawsuit filed in San Luis Obispo County Superior Court said Smart’s body was buried in Ruben Flores’s backyard and he moved the body "under cover of darkness" to another location a few days after investigators searched his property in February 2020.Ruben Flores, 80, pleaded not guilty to accessory after murder on Monday, and his son, Paul Flores, 44, pleaded not guilty to murder.Booking photo of Paul Flores (pictured left) and his father Rueben Flores (shown right).