All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If you mean performing Ruqyah just by mentioning the number of the verse without reciting it, then we are not aware of any evidence about this. The Ruqyah should be performed by reciting the Quran, supplicating, and reciting the legislated mention of Allaah; for more benefit, please refer to Fatwa 13249 and 81643.
It is not an obligation for a person who performs Ruqyah on someone else to be aware of the place of magic and the like; rather, it is sufficient for him to perform the legislated Ruqyah and supplicate Allaah to invalidate the magic, and if Allaah wishes, He will invalidate it and no effect will remain of it.
If it is possible to know the place of magic and remove it [magic], then this is better because this is more effective in removing the evil of magic, as it happened with the story of the Prophet when Labeed ibn Al-A’sam worked out a magic spell on him.
Among the means by which one might know the place of magic is by supplicating. Thanks to supplicating, Allaah may enable some people to see a dream about the place of magic. Sometimes, the person who performs Ruqyah may know this by making the jinn by whom the person is possessed speak, and the like.
For more benefit, please refer to Fatwa 82918.
As regards the claim that a force comes out from the belly of the person who performs Ruqyah and when he recites the verses it has an effect on the sick person, then this is similar to the claim of magicians, and the same thing applies to the act which you mentioned in the question.
The fact that they recite some Quranic verses may be a way of deceiving the general public and it is most likely that they add some terms to the recitation without the people taking notice of it.
Therefore, one should be careful from asking someone who is not known to have a correct creed and a good conduct to perform Ruqyah on him.
For more benefit, please refer to Fatwa 89926 and 18831.
Allaah Knows best.