Should the object always be placed after the verb, and is a target and an object the same thing?
As a native Chinese citizen &amp; Chinese speaker, I can confirm that that placement is wrong, or at least partially.

警察那天不停地在警察局对他审问了几个小时 sounds quite weird. This sounds like:


  The police repeatedly "interrogated him in the office" for several hours.


...which errorneously overemphasized the place.

My version (that makes sense):


  警察那天在警察局不停地对他审问了几个小时。


Usually, places and locations should come before manners. If they come after manners, the only case in which it makes sense is when you want to emphasize the place. Generally, whatever closer to the verb is more "important". Compare:

他高兴地在教室里跳了起来。(Emphasizing place)
他在教室里高兴地跳了起来。(Emphasizine manner)