The research study was premised on the problem that ,Violation of human rights at the time of interrogation of suspects is a major challenge, which affects the suspect’s right under article 13(6) (a) of the Constitution of the United Republic of Tanzania . The laws and court decisions emphasize on the protection of human rights. However, there are no serious mechanisms established by the legal framework and law enforcing organs, which can reduce the violation of human rights at the time of criminal interrogation. The study confined itself in testing the hypothesis that intended to prove that, violation of Human rights in the process of interogating criminal suspects is a common practice among the law enforcing authorities in Tanzania initiated by administrative and legal factors. Thus the main objective of the study was to show the causes of human rights violation on suspects during criminal investigations by verifying the weakness of the legal frame work and the law enforcing organs. The findings of verified that, issues such as; impunity of police officers, unexpedite interrogations, partisan policing, unpressumptive of innocence and unethical police to be reasons for the police force to engage in the violations of the suspect’s rights. Also, the legal framework obtains loopholes that enhance torturous acts upon the criminal suspects by the police officers. The major recommendations for the way forward were that the police force should recruit experts in criminology and forensic and the parliament to enact a single legislation that shall protect the rights of criminal suspects under custodial investigation.