The agency, which started its probe in June, will file its final report before the trial court next week, CBI sources said here.
They said a recommendation for probe against state police officers for botched up investigation will be made.
The final report will also mention questionable actions of fathers of the girls, an uncle and main witness Nazru, also a distant relative, leaving it to the court to take further action, they said.
"The CBI has not explained why they would commit suicide. If we don't get justice we will kill ourselves," said the father of one of the girls.
"How is it possible that the girls could have committed suicide together from a tall tree...I appeal to Modiji to ensure that we get justice," he said.
The girls, who were 14 and 15, were found hanging from a mango tree near their village on May 28, a day after they were reported missing.
"Based on around 40 scientific reports, CBI has concluded that the two minor girls in the Badaun case had not been raped and murdered as had been alleged in the FIR. Investigation has concluded that it is a case of suicide," CBI spokesperson Kanchan Prasad said in Delhi.
CBI claims that the two girls had allegedly committed suicide at about 2 AM on May 28 morning even as frantic efforts were being made by their families to trace them in the village.
