CHANTILLY, Virginia — The devastated parents of missing University of Pittsburgh student Sudiksha Konanki are now convinced she drowned while on spring break in the Dominican Republic, they revealed to The Post Tuesday.“Both sides of the authorities have shown us how high the ocean waves were at the time of the incident, and both sides of the authorities have clarified the person of interest was not a suspect from the beginning,” Subbarayudu Konanki, the missing coed’s father, said from the family home in Virginia.“It is with deep sadness and a heavy heart that we are coming to terms with the fact our daughter has drowned,” he said.“This is incredibly difficult for us to process.”They also asked that Joshua Riibe, the 22-year-old Iowan who was the last to see Konanki alive, be allowed to leave the Caribbean nation where he has been detained while the investigation into the disappearance continued.Earlier Tuesday, Konanki’s hometown Loudoun County Sheriff’s Office also said investigators don’t think he was involved.Riibe’s lawyer filed a legal “habeas corpus” request Monday demanding that he be allowed to return to the US because he has not been charged with wrongdoing.A court hearing on that request is scheduled for later today.The change of heart from the family comes one day after Subbarayudu and his wife, SreeDevi, filed a letter with authorities in the Dominican Republic asking that their 20-year-old daughter be declared legally dead 12 days after she disappeared from a Punta Cana beach while on spring break with friends.Konanki’s parents had previously led the charge to demand Dominican authorities expand their investigation into her disappearance — and probe whether she was the victim of foul play.Konaki, a pre-med student at Pitt, arrived at the upscale RIU Hotel & Resort on March 3 for spring break and disappeared on March 6 after an overnight swim with Riibe.Her parents said the international media attention has made the...