Hagatña, Guam – SHAWN N. ANDERSON, United States Attorney for the Districts of Guam and the Northern Mariana Islands, announced that defendant, Gregorio Concepcion Tyquienco, age 72, was sentenced on February 4, 2025, in the District Court of Guam to 30 days imprisonment followed by one year of supervised release for Contempt of Court, in violation of 18 U.S.C. § 401(3). The Court ordered Tyquiengco to pay $1,537.04 as restitution (representing the fees and mileage paid to him as a juror during a trial), a $2,000 fine, and a mandatory $25 special assessment fee.
Tyquienco was a juror in the trial of United States vs. Raymond John Martinez and Juanita Marie Quitugua Moser in the District Court of Guam. Between October 11, 2018, and December 27, 2018, Tyquienco knowingly disobeyed the Court’s instruction not to discuss the case with anyone outside of the jury’s deliberative process. During the trial, and prior to jury deliberation, Tyquienco discussed what verdict he would render with brothers William Topasna Mantanona and John T. Mantanona, aka “Boom.” Tyquienco knew Boom was working as a member of the defense team. He knew Boom previously but did not disclose the association to the Court. Tyquienco was asked by William and Boom to be the jury foreman and to issue a “Not Guilty” verdict regardless of the evidence. These discussions violated the clear and specific daily orders of the Honorable Frances Tydingco-Gatewood, Chief Judge, District Court of Guam. After a mistrial was declared, Boom met with Tyquiengco and gave him $1,100 in cash.
“Jury tampering is an affront to the Rule of Law,” stated United States Attorney Anderson. “Our citizens and the accused expect fair legal proceedings that result in justice. Jurors and witnesses make great sacrifices to fulfil this important civic duty. This case sends a message that the Department of Justice will hold accountable those who violate this public trust.”
“The integrity and impartiality of jurors and their deliberations are essential to our criminal justice system,” said FBI Honolulu Special Agent in Charge David Porter. “Those who tamper with this important civic responsibility attempt to deny our communities the justice they deserve. As reflected by this investigation, the FBI is committed to protecting our legal processes and will bring to justice those who act to corrupt it.”
The case was investigated by the Federal Bureau of Investigation and prosecuted by Assistant United States Attorney Rosetta L. San Nicolas in the District of Guam.
