Investigators are trying to determine the cause of a plane crash that killed eight parachutists and their pilot in Sweden on Sunday. Witnesses say they heard a loud noise before the single-engine GippsAero GA8 Airvan plunged nose-down into Storstarskar island, the Local reports. Some witnesses say they saw skydivers try to jump from the plane just before the crash. There were no survivors. Authorities say the crash happened around 2pm, shortly after the Australian-made aircraft took off from Umea Airport in northern Sweden, the AP reports. Investigators say the plane did not carry a black box, so they will have to rely on witness statements, examination of the wreckage, and data from onboard phones that measured height and position. (Last month, nine people died when a skydiving plane crashed in Hawaii.)