这句话是定语从句吗

这句话是定语从句吗　The boss in whose department Mr King worked called at the hospita 如果是 那in是介词不应该是宾语从句吗 但是网上说这句是whose引导的定语从句

是定语从句，如果把这个从句去掉，句子结构是完整的，如果是宾语从句，去掉之后句子就会缺少宾语，使句意不完整
The boss in whose department Mr King worked called at the hospital.
这句话中in whose department Mr King worked 用来修饰the boss，如果去掉之后，句子变成The boss called at the hospital. 句子依然完整，所以in whose department Mr King worked起修饰作用，因此是定语从句