SAN FRANCISCO (AP) — Two skydivers were killed Saturday during a tandem jump in northern California, authorities said Saturday. 
 
 Their bodies were found in a Lodi-area vineyard after someone reported that the skydivers hit the ground without an open parachute, San Joaquin County Sheriff's Deputy Les Garcia said. 
 
 It appeared the parachute did not deploy until after impact, he said. 
 
 Authorities were working to identify the bodies, but Riley said it appears the victims, both males, were in their 20s. One was an instructor, he said. 
 
 They had jumped from the Parachute Center, a popular skydiving school in the state's Central Valley whose website declares it "one of the largest and oldest drop zones in the United States," launched in 1964. 
 
 The website offers an introductory tandem jump with an instructor for $100, from 13,000 feet. 
 
 The center has been in the news before. In May, a small plane carrying 17 skydivers took off from the Parachute Center and landed upside-down after clipping a pickup. The worst injuries were minor cuts and scrapes. 
 
 And in February, the Lodi News-Sentinel reported that a solo skydiver had died after a parachute malfunction at the center. 
 
 Parachute Center owner Bill Dause told KCRA-TV the instructor in Saturday's deadly jump was an independent contractor who has made about 700 jumps. 
 
 "The parachute failed to eject properly. We have no explanation why," Dause said. "The only thing it looks like is something may have gone out of sequence (and) that may have caused the problem." 
 
 An exact cause will be determined by the Federal Aviation Administration. ||||| Two men were killed in a tandem parachute jump Saturday morning in Acampo, officers said. 
 
 Deputies responded to a report of a skydiver crashing to the ground about 10 a.m. in a field near the Lodi Parachute Center, the San Joaquin County Sheriff's Office said. Witnesses reported that they didn't see a parachute open as the skydivers plummeted down. 
 
 When deputies arrived, they found the tandem jumpers dead in a field near the parachute center, officials said. 
 
 "Deputies responded out to the scene and came across a tandem jumping pair that did impact the ground without their shoot deploying," said Lt. Randy Johnson with the San Joaquin County Sheriff's Department. 
 
 Deputies believe the parachute did not deploy until after impact, officials said. 
 
 Lodi Parachute Center owner Bill Dause said the instructor was an independent contractor with about 700 jumps of experience. 
 
 "The parachute failed to eject properly. We have no explanation why,” Dause said. “The only thing it looks like is something may have gone out of sequence (and) that may have caused the problem" 
 
 Dause continued business as normal throughout the course of the day, telling KCRA 3 there was another malfunction but it was remedied without incident. 
 
 “I am always liable but I am not concerned. We didn’t do anything wrong,” Dause said. "It's a love of the sport. You keep going. You feel sorry for the people who can't participate any longer." 
 
 The identities of the two men have not been released. 
 
 The Federal Aviation Administration has been contacted and will be taking over the investigation of this incident, officials said. 
 
 No other information was released. ||||| File photo - A paraglider is seen prior to the ski jumping event in Oberstdorf, Germany, which is the first station of the Four-Hills Ski Jumping tournament on December 29, 2015. (Photo: Christof Stache, AFP/Getty Images) 
 
 Authorities in northern California were trying to determine Sunday what caused the death of two skydivers in a tandem jump Saturday, one of whom was 18 and whose family watched as he hit the ground. 
 
 Officers found the bodies in a field near the Skydive Lodi Parachute Center in Acampo, the San Joaquin County Sheriff's Department said in a statement. The parachute did not appear to deploy until after impact. 
 
 The other victim was an instructor, according to Deputy Les Garcia. He did not release the names. 
 
 "The parachute failed to eject properly. We have no explanation why," Bill Dause, owner of the Parachute Center, told KCRA-TV. "The only thing it looks like is something may have gone out of sequence (and) that may have caused the problem." 
 
 The 18-year-old was jumping for the first time and had a brother and several other people with him at the skydive center, Dause said. The instructor was a skydiving veteran who had about 700 previous jumps, he said. 
 
 The wind and other conditions were "perfect" at the time of the jump, Dause said. "Conditions had nothing to do with it." 
 
 Deputies received a 911 call around 10 a.m. from someone reporting a skydiver hit the ground without an open parachute, according to the statement. The Federal Aviation Administration will investigate the cause of death. 
 
 The Parachute Center, which opened in 1964, is based in one of the largest drop zones in the U.S., according to the business's website. It offers an introductory jump, in tandem with an instructor, from 13,000 feet for $100. 
 
 Experienced skydivers can jump for $15. 
 
 The skydive center was in the news in May, when a small plane carrying 17 skydivers landed upside-down after clipping a pickup. The worst injuries were minor cuts and scrapes. 
 
 Saturday's deaths marked the second fatal jump at the Parachute Center this year. In February, a solo skydiver was killed when a parachute malfunctioned. 
 
 "We didn’t do anything wrong,” Dause told KCRA-TV. "It's a love of the sport. You keep going. You feel sorry for the people who can't participate any longer." 
 
 Contributing: John Bacon, Greg Toppo, USA TODAY 
 
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– Two skydivers were killed Saturday during a tandem jump in northern California, reports the AP. Their bodies were found in a Lodi-area vineyard after someone reported that the skydivers hit the ground without an open parachute, San Joaquin County Sheriff's Deputy Les Garcia said. It appeared the parachute did not deploy until after impact, he said. Authorities were working to identify the bodies, but it appears the victims, both males, were in their 20s. They had jumped from the Parachute Center, a popular skydiving school in the state's Central Valley whose website declares it "one of the largest and oldest drop zones in the United States," launched in 1964. Parachute Center owner Bill Dause told KCRA-TV the instructor in Saturday's deadly jump was an independent contractor who has made about 700 jumps. "The parachute failed to eject properly. We have no explanation why," Dause said. "The only thing it looks like is something may have gone out of sequence (and) that may have caused the problem." The website offers an introductory tandem jump with an instructor for $100, from 13,000 feet. The center has been in the news before. In May, a small plane carrying 17 skydivers took off from the Parachute Center and landed upside-down after clipping a pickup. The worst injuries were minor cuts and scrapes. And in February, the Lodi News-Sentinel reported that a solo skydiver had died after a parachute malfunction at the center. “I am always liable but I am not concerned. We didn’t do anything wrong,” Dause said. "It's a love of the sport. You keep going. You feel sorry for the people who can't participate any longer." An exact cause will be determined by the Federal Aviation Administration.