Three people have been killed and three others injured after a helicopter crashed while dropping off skiers on the Petit Combin mountain in the Swiss Alps. The B3-type helicopter crashed at a landing site during a heliski drop-off on Tuesday, the Wallis regional police force said in a statement. The statement said: “Having reached the summit of a mountain culminating at 3,668 metres above sea level, for a reason that the investigation will have to determine, the aircraft slid down the northern slope.” The pilot, a mountain guide and his four clients were onboard. Their identities have not been released. Seven helicopters were sent to the site as part of the rescue effort. Two injured people were treated quickly before being airlifted to hospital in Sion, the capital of the Valais, or Wallis, canton. A third person was rescued afterwards, the police said. “The three other occupants of the aircraft were unfortunately found lifeless,” the statement said. On Monday, elsewhere in the south-eastern Valais canton, three people were killed in an avalanche, including a 15-year-old boy from the United States.