he was seen to enter the building about the time the crime was committed.后面the crime was committed是定语从句还是时间状语从句,前面可以加when吗?补：在定语从句中，当先行词是表时间、地点等名词时，关系副词when,where可以省略；还有the reason,way是先行词时也可以省略关系副词。

he was seen to enter the building about the time the crime was committed.后面the crime was committed是定语从句还是时间状语从句,前面可以加when吗?
补：在定语从句中，当先行词是表时间、地点等名词时，关系副词when,where可以省略；还有the reason,way是先行词时也可以省略关系副词。