里 is a half free morpheme, which means it always has to be combined with another morpheme. 这里，哪里，那里，里面，里边。 For example 房间里有一个小女孩。 房间里面有一个小女孩。 房间的里面有一个小女孩。 They are all the same, the subjects are all noun-phrase. 房间里边=房间里面=房间里 So you don't have to use 里 or 边 all the time. But you can not take 里 as a single word. 里面有一只老虎 but not 里有一只老虎

你的问题很有趣

I think both of them needs to be put in specific context，such as, 我的书放在书包里／里面。