LYNN – In the hours before she was discovered in Flax Pond Wednesday, John Nunes almost broke off the search for his missing wife and asked the professional searcher he hired to refocus his efforts on Sluice Pond.”I said, ‘No, we need to check the other contact,” Rick Horgan said Thursday.That contact appearing as a dark mass on Horgan’s specialized sonar equipment turned out to be a missing black Lexus with Alice Nunes’ body inside it. Police divers, aided by Lynn firefighters, used search information provided by Horgan to locate the Lexus 40 feet off Carter Road Wednesday afternoon.For Horgan, a West Lynn native who developed a love of underwater diving at the age of 17, finding the 58-year-old grandmother was his latest successful attempt to unravel an underwater mystery.It was Horgan in July 1999 who used sophisticated underwater search equipment to pinpoint the location of John F. Kennedy Jr.’s private plane and the bodies of Kennedy, his wife and sister-in-law.Horgan spent months helping investigators search the ocean off Florida for remains of the Challenger space shuttle explosion and he searched a Texas lake to retrieve parts of the Columbia shuttle wreckage.He has worked for years under a Navy contract locating the submerged wrecks of military as well as commercial and privately owned aircraft. Horgan was en route to a job in New York last July 4 when he stopped in Lynn to join his family for Independence Day celebrations.Searchers had already spent six months diving into local ponds and scouring the Saugus River for signs of Nunes’ Lexus.”We took a look in the river on our own,” he said.His search did not locate the Lexus but it prompted Horgan’s brother, Tim, who owns Stoneham Boat Center, to mention Rick’s search capabilities to John Nunes.Nunes called Rick Horgan about two weeks ago and hired him to conduct a new round of water searches in hopes of finding his wife. Horgan said Sluice and Flax ponds were the logical place to start the search.The two ponds are near the Wyoma Square cellular telephone transmission tower that relayed Alice Nunes’ calls to her daughter and husband last Dec. 15. During the call to her daughter, Nunes, according to police, said, “I’m about to hit some water.” In her call to her husband, Alice Nunes said she was in Lynn.”Both ponds can hide a car,” Horgan said, “The only way into Sluice is the boat ramp (by Briarcliff Lodge) while there are several ways into Flax.”After searching Sluice earlier this week, Horgan, with John Nunes at his side, crisscrossed Flax on Tuesday in a small boat pulling a “tow fish” behind it. The torpedo-shaped tow fish beams out “scans” that show up as images on a computer screen in the boat. Using an extremely accurate global positioning device and a search grid, Horgan monitored the scans on Tuesday as he searched Flax and marked two contacts for more detailed searches.One of the contact resembled a car except for the object protruding from one end. The other looked like an upside down car submerged in Flax near the playground located on the pond’s bank. Horgan said Nunes was convinced the upside down car was his wife’s black Lexus.”He felt like we had found it,” Horgan said.But when divers on Wednesday discovered the car was a stolen vehicle dumped in Flax years ago, Nunes took the letdown hard.”It was an emotional swing for both of us when it was the wrong car. He wanted to go to Sluice. I said, “No, we have to check the other.'”Divers pulled the black Lexus out of Flax at 3:40 p.m. Wednesday and found a woman’s body and Alice Nunes’ work identification inside the car. The object jutting from the car’s outline on Horgan’s side scan turned out to be the Lexus’ open trunk lid.Horgan has mixed feelings about helping John Nunes and his loved ones end their nearly year-long search.”You sort of feel a little bit like they probably do: sad, but glad for closure.”