arsonist [arsonists](one who has committed the act of arson) noun [UK: ˈɑː.sə.nɪst] [US: ˈɑːr.sə.nəst]The arsonist was never apprehended. = Nunca cogieron al pirómano.
firebug(pyromaniac or arsonist) noun [UK: ˈfaɪə.bʌɡ] [US: ˈfaɪər.ˌbəɡ]
pyromaniac [pyromaniacs](one who is obsessed with fire) noun [UK: ˌpaɪ.rəʊ.ˈmeɪ.niæk] [US: ˌpaɪro.ʊ.ˈmeɪ.niæk]