Bummer. Isn't it Salvadorian Air Force though?
It was with the Salvadoran AF between 1968 and 1974.
More correctly, it is parts of the wrecks of three different Mustangs that served with the FAS during that time, and were rebuilt into one aircraft after they were all purchased by a buyer in the US.
Here's the ownership history (courtesy mustangsmustangs.com):
1974: N36FF, Jack Flaherty, wreck
1975: John Herlihy, Half Moon Bay CA
1975: N4151D, Gordon Plaskett, King City CA
1977: rebuilt using 44-74012, first flight Nov 22, "TF-660"
1981: Ben Bradley, Fort Lauderdale FL
1981: Basil Deuschle, Pompano Beach FL
1983: Don Whittington, Fort Lauderdale FL
1987: Robert Waltrip / Air SRV Inc / Lone Star Flight Museum, Houston TX
1988: Doug Arnold / Warbirds of Great Brittan, Biggin Hill UK - stayed in U.S.
1991: William Hane, flies as 44-84660, TF-660
2008: for sale
2009: Dec - N4151D sold to Lone Star Flight Museum, Galveston TX
Restoration at Ezell Aviation
rep. to be painted as 359th FG "Galveston Gal"
2010: Mar 25 - Reg to Texas Aviation Hall of Fame
2011: Mar 7 - repainted and flown as "Galveston Gal". Work performed: full IRAN inspection, replacement of lower RH longeron, extended vertical stabilizer, main gear re-bushing, replacement of wing fuel cells and a very nice paint job. First flight by Tommy Gregory.
2013: Oct 23 - Galveston Texas: 44-73458 went down into Halls Lake near Chocolate Bay, both Pilot and Passenger did not survive. Condolences to the Lone Star Flight Museum, family and friends of the pilot and passenger.