Meaning of "Invariably Poirots calls all the suspicions together..."

[Goran]

English Language Tests, Intermediate level

ESL/EFL Test #29 "Who has done it?", question 8

Invariably Poirots calls all the ......... together in the last part of the story.

(a) suspicions
(b) suspecting
(c) suspected
(d) suspects

English Language Tests, Intermediate level

ESL/EFL Test #29 "Who has done it?", answer 8

Invariably Poirots calls all the suspects together in the last part of the story.

Correct answer: (d) suspects

Your answer was: incorrect
Invariably Poirots calls all the suspicions together in the last part of the story.
_________________________

please explain to me what this sentence means

thank you
Goran

[Conchita]

In other words:

Inspector Poirot always calls a meeting of the suspects (the people who are thought to have committed the crime) near the end of the story.