A group of FBI investigators, in connection with the 1975 disappearanc

From Ron (Manhattan Prep)

The modifier placement is better in choice (E) than in the other choices.

The modifier "in connection..." describes the searching of the farm, not the group of investigators, and so should be attached to the words describing the act of searching. Choice E is the only choice in which this modifier is placed in a sensible location.

There's no problem with "is being searched...".

The sentence could also be written in the active voice ─ "a group of investigators is searching xxxxxx in connection with yyyyy..." ─ but that doesn't mean anything is actually wrong with the passive construction.

In 1993, I graduated from Manual High School.
--> Here, the modifier applies to the stuff that comes after it ─ because nothing comes before it.

This is not a principle that applies to modifiers sandwiched between two commas. In most of those cases, the modifier will describe the stuff that comes before it (as do most english modifiers).

e.g.
Manual High School, in central Louisville, is a "magnet school" that enrolls students from all areas of the city.
--> This is a perfectly respectable sentence, in which "in central Louisville" describes the school.

In fact, if you see a prepositional phrase that's right after a noun (like that one), then its purpose is almost always to describe the noun and NOT the following stuff.

If you wanted the phrase to be adverbial, you'd throw it at the start of the sentence instead.

i.e.

If you have NOUN, in connection with xxxxxx, VERB..., then "in connection with xxxxx" should, ideally, describe the NOUN.

If you wanted this modifier to describe the action, that would be better written as "In connection with xxxxxx, NOUN VERB ..." ─ a construction in which the adverbial nature of the modifier is not debatable.

GMATNinja, Could you help to explain the usage of "being" in answer choice (E)?