"Located" is the past participle of the verb "to locate" (meaning to place or to find). So it's a verb form, and it has two uses -- 1) as a participial modifier of nouns, working like an adjective or 2) in combination with some form of the verb "to be" (here "is") to make a verb in the passive voice. I don't understand your example about the mall, so I'll make up my own. Suppose I write
I'm completely lost, until -- finally! -- the mall is located by my car's
We can tell this is the passive-voice usage because we can transform the clause into the active voice in three steps:
- The object of the preposition of agency, "by", (here, "my car's GPS) becomes the subject.
- The passive becomes the active: "is located" -> "locates"
- The subject ("the mall") becomes the object.
This gives us
My car's GPS locates the mall.
Now consider the sentence
The mall is located by the river.
Here "located" is a participle that serves as an adjectival complement to "mall," telling us which mall we're talking about. It's the mall down by the river. Note that the same three-step trick won't work. "By" is still a preposition, but it's one of location, telling us where; not agency, telling us who. If we try it anyway, we get
The river locates the mall.
Which makes no sense.