An American family of four vacationing in Mexico has been found dead in the condo they were renting, authorities say. Mexican police discovered the bodies of Kevin Wayne Sharp; his wife, Amy Marie Sharp; their 12-year-old son Sterling; and 7-year-old daughter Adrianna on Friday during a welfare check in the Mexican resort town of Tulum. Police say there were no signs of foul play at the scene, and no cause of death has been given. Autopsies are being conducted in Mexico, where Mexican authorities are in charge of an investigation into the Sharps’ deaths, according to the U.S. State Department. Friends and family had reportedly grown concerned after the Sharps failed to return to the U.S. as planned on Wednesday. “I guess we were all kind of hoping for the best—that maybe they were just planning to stay another day,” Jana Weland, a cousin of Amy Sharp, told ABC News. “To my knowledge, they went to sleep and never woke up,” she said.