NEW YORK (REUTERS) - A son-in-law of Osama bin Laden, who once served as a spokesman for al Qaeda, on Tuesday failed to win the dismissal of a U.S. indictment accusing him of conspiring to kill Americans.

The defendant, Suleiman Abu Ghaith, also failed to win the suppression of statements he made while being interrogated by FBI agents nearly nine months ago, as he was being flown to the United States from Jordan to face the U.S. conspiracy charge.

U.S. District Judge Lewis Kaplan in Manhattan rejected Abu Ghaith's arguments that federal prosecutors brought their case too late and violated his due process rights.

The judge found a lack of "credible evidence" that the United States could have indicted Abu Ghaith sooner and ended what the defendant called his "continual detention" in Iran from 2002 to January 2013, but instead deliberately waited to obtain a "tactical advantage." Kaplan also rejected Abu Ghaith's contentions that he had not been read his Miranda rights, including the right to remain silent and have a lawyer present, until well after questioning began; that the FBI ignored his requests to talk with a lawyer; and that any statements he made were involuntary.

Abu Ghaith's lawyers had argued that their client had been physically and psychologically coerced into answering agents'questions "out of a combination of disorientation, fear, isolation, fatigue and sensory deprivation." But Kaplan said Abu Ghaith was "treated humanely" during the flight, where he had been given a medical evaluation, was regularly offered food and water, and was allowed to pray, stretch, take bathroom breaks and nap.

"Abu Ghayth was not overcome by fear such that his will was overborne and his ability to act voluntarily was compromised,"Kaplan wrote. "The government has offered consistent and credible testimony that Abu Ghayth was treated well and that he was competent to speak with the FBI throughout the flight. Abu Ghayth has offered scant evidence to the contrary." Stanley Cohen and Geoffrey Stewart, the lawyers for the defendant, did not immediately respond to requests for comment.

A spokeswoman for U.S. Attorney Preet Bharara in Manhattan declined to comment.

Abu Ghaith is one of the highest-ranking al Qaeda figures to face trial in the United States for alleged crimes connected to the Sept. 11, 2001, attacks.

The defendant pleaded not guilty and his trial is scheduled to begin on Jan. 21, 2014, court records show.

U.S. forces in Pakistan killed bin Laden, who masterminded the attacks, in May 2011.

The issue of whether statements made during interrogation were voluntary also came up in the U.S. case against accused Boston Marathon bomber Dzhokhar Tsarnaev, who allegedly made incriminating statements to investigators in his hospital room soon after his capture in April.

Tsarnaev pleaded not guilty to the bombing in July.

The case is U.S. v. Abu Ghayth, U.S. District Court, Southern District of New York, No. 98-cr-01023.