The Standard version is wrong. The subject ie FBI is in 3rd person singular(He/she/it). Thus it can only be FBI JOINS.

Two good examples of collective nouns are "team" and "government", which are both words referring to groups of (usually) people. Both "team" and "government" are count nouns. (Consider: "one team", "two teams", "most teams"; "one government", "two governments", "many governments"). However, confusion often stems from the fact that plural verb forms are often used in British English with the singular forms of these count nouns (for example: "The team have finished the project."). Conversely, in the English language as a whole, singular verb forms can often be used with nouns ending in "-s" that were once considered plural (for example: "Physics is my favorite academic subject"). This apparent "number mismatch" is actually a quite natural and logical feature of human language, and its mechanism is a subtle metonymic shift in the thoughts underlying the words.