In my humble understanding of the sources, both, but let me refer you to the university's source page and the ​CMC, which directly researches this phenomenon. I am doing this because I am not a specialist in meteorological phenomena, and although I did my great portion of homework, my knowledge will not be enough to explain any matter to mathematician.. ;>

http://cmc.org.ve/portal/proyectos.php?proyecto=8

the study of Doctor Ángel Muñoz http://www.azulambientalistas.org/Resumen-de-diversos-aspectos-estudiados-cientificamente-sobre-el-Relampago-del-Catatumbo.html