John T. Mantanona, a retired police officer, has been sentenced to 60 months in federal prison for obstructing justice. The case, presided over by Senior District Judge John C. Coughenour at the District Court of Guam, involved Mantanona's attempt to influence a juror in violation of 18 U.S.C. § 1503. Along with the prison sentence, the court ordered Mantanona to serve two years of supervised release and pay a $30,000 fine and a $100 special assessment.
The charges against Mantanona originated from a federal jury trial conducted from October to November 2018. During the trial of United States v. Raymond Martinez and Juanita Moser, Mantanona, a former member of the Guam Police Department and FBI task force, was hired as an investigator. He attempted to sway juror Gregorio Tyquiengco to vote "not guilty" and to influence other jurors towards the same verdict, aiming for a mistrial. Subsequently, a mistrial was declared. Mantanona had provided Tyquiengco with $1,100 in total.
Tyquiengco acknowledged his actions, pleading guilty to contempt of court in violation of 18 U.S.C. § 401(3) and received a 30-day prison sentence along with a year of supervised release. He was also ordered to return the money gained for his juror service.
Additionally, William Topasna Mantanona, who is connected to John T. Mantanona, also faced legal consequences. He pled guilty to making a false statement to a government agent, as per 18 U.S.C. § 1001(a)(2), having falsely denied involvement in the scheme during an interview. He was sentenced to six months in prison, followed by two years of supervised release, and fined $5,000 in the district court on August 26, 2021.
U.S. Attorney Shawn N. Anderson commented on the case, emphasizing the importance of public trust in the judicial system and the commitment of the Department of Justice to accountability. Lucy Cabral-DeArmas, the Special Agent in Charge for Homeland Security Investigations Hawaii, reiterated the breach of trust Mantanona's actions represented. FBI Honolulu Special Agent in Charge David Porter highlighted the crucial nature of the FBI’s anti-corruption efforts.
The case was a collaborative investigation conducted by the FBI and Homeland Security Investigations, with prosecution by Assistant United States Attorney Rosetta L. San Nicolas in the District of Guam.
