A foreigner living in a Swedish village wrote to the Ombudsman complaining that he had been ill-treated by the police, simply because he was a foreigner
一个住在瑞典乡村的外国人写信给司法特派员，抱怨说他受到警察虐待，原因就是因为他是个外国人
……
如果属于宾语从句里，那个逗号看着很奇怪，用逗号分割两个从句（宾语从句和原因状语从句）？