noun
arson; arsonist
Refers both to the crime of arson and to a person who commits arson. Context determines whether it means the act or the perpetrator.
警察は放火犯の疑いで男を逮捕した。
The police arrested a man on suspicion of arson.
その火事は放火犯によるものと見られている。
The fire is believed to be the work of an arsonist.
放火魔 is a more sensational term for a serial arsonist or pyromaniac, while 放火犯 is a neutral legal term.
Compound of 放火 (ほうか, 'arson') and 犯 (はん, 'crime' or 'criminal').