The trial began Tuesday in Nassau County for a man accused of killing his parents in 2009.
Gregory Larkin could face the death penalty if convicted in the deaths of 75-year-old Richard Larkin and 73-year-old Myra Larkin.
Larkin was found with his parents' missing SUV hours after the couple was found dead in their Amelia Island home in April 2009. Deputies said someone who went to the couple's home to check on them after they failed to show up for a conference found them dead.
According to the Nassau County Sheriff's Office, the victims were found in different rooms of the home and died of blunt force trauma. Investigators believe the couple had been dead for several days.
Because there were no signs of forced entry and because the two victims were found in different parts of the home, investigators quickly announced that the couple's son was a person of interest in the case.
He was found that night in a hotel at Jacksonville International Airport with the missing SUV parked outside.
Investigators said several pieces of evidence -- including his mother's blood on Gregory Larkin's clothing -- led to the murder charges.
Deputies said they also had what they believe was the murder weapon.
Investigators said at the time they were not sure of a motive for the slayings, although there were reports of financial problems in the family.
Gregory Larkin and three other siblings ran a family-owned dive shop in Costa Rica, but Gregory Larkin had returned to the U.S. in January and had been living with his parents.
Gregory Larkin told investigators he had been in Mexico since Easter Sunday and had just returned to town. He said he was robbed while in Mexico and the keys to the family's SUV were taken, so he had to get a room at an airport hotel after returning to town.
Seagraves said travel documents verify that Larkin did make that trip, so they believe he killed his parents before he left town and their bodies were not found for a week.