It was not shown in manga nor in the anime. However it was said that the villages hired the Akastki to capture the first two tailed beast. Im betting the first was the 5 tails because naruto sensed the "mallace" from a mile away. The 7 tails was probably because she was the most powerful in the village and thus because she did not have control of the tailed beast that they hired akastki to help them solve their problem. I also have a feeling that the removal of the 3 tails was done by his own village to break control of the Mizakage's control over the village (thus an easy target).
