The suspended superintendent, Leiataua Luatimu Samau, is the officer investigating the more than 200 criminal charges against the suspended Police Commissioner, Fuiavailili Egon Keil.
RNZ reports, the suspended corporal is the complainant of charges of inciting to murder, procure to murder and counsel to murder against Fuiavailili.
The two other suspended officers were involved in the arrest of Fuiavailili only days after he was reinstated by cabinet after earlier charges against him were dropped for insufficient evidence.
A police source said the Ministry of Police must call an urgent meeting to discuss the situation and to make sure that justice will prevail.
One senior officer told our correspondent that he suspects politics was behind the decision to suspend more senior police officers.
Last month, a cabinet reshuffle saw the Prime Minister, Tuila'epa Sa'ilele Malielegaoi take on the police portfolio.
The government said returning oversight of the police to the prime minister reaffirmed the importance placed on law and order.
Last month, cabinet called a commission of inquiry to review the police department, as well as the conduct and performance of the suspended assistant police commissioner, Mulinuu Mulinuu.
Fuiavailili is seeking a court decision to grant him access to the police evidence needed to build his defence.
Photo: RNZ (Autagavaia Tipi Autagavaia Samoa Assistant Police Commissioner Samoa Mulinuu Mulinuu )