Joran van der Sloot pleads not guilty as Natalee Holloway's mom looks on

Joran van der Sloot, the main suspect in the unsolved 2005 disappearance of American teenager Natalee Holloway, appeared in court in Birmingham, Alabama, on Friday, pleading not guilty to federal extortion and wire fraud charges.

Holloway's mom, Beth Holloway, looked on as van der Sloot, who is accused of trying to extort her, walked into the courtroom.

Van der Sloot, a Dutch citizen, chose not to use an interpreter in court, saying, "My English is perfect."

Beth Holloway's attorney said in a statement Friday, "Today is a victory for Beth and everyone who has offered their well wishes, prayers, and work on the case for nearly two decades. And more victories are sure to come."

Natalee Holloway's father, Dave Holloway, said in a statement Friday, "While filled with mixed emotions, I am confident that today was an important step toward accountability and hopefully, justice."

Van der Sloot was flown to the U.S. on Thursday from Peru, where he had been serving a 28-year sentence for the 2010 murder of 21-year-old Stephany Flores. Plans for his extradition were announced last month.

"For 18 years, I have lived with the unbearable pain of Natalee's loss," Beth Holloway said in a statement Thursday. "Each day has been filled with unanswered questions and a longing for justice that has eluded us at every turn. But today, with her perpetrator's extradition to the United States, I am hopeful that some small semblance of justice may finally be realized, even though no act of justice will heal the pain we've endured."

Mark White, attorney for Dave Holloway, called the extortion and wire fraud case "some form of accountability," but "not accountability for the ultimate transgression of what a lot of people think this person did to their child."

White told ABC News on Thursday that he feels "more than 100%" certain that van der Sloot knows where Natalee Holloway's body is located.

"Beth and Dave Holloway, they have been living every parent's worst nightmare," he said. "We all hope ... that somehow the truth will come out."

Holloway, an 18-year-old from Alabama, went missing in May 2005 on a high school graduation trip in Aruba. She was last seen with a group of young men, including van der Sloot, then 17.

Van der Sloot, who was detained as a suspect in Holloway's disappearance and later released, was indicted by an Alabama federal grand jury in 2010 for allegedly trying to extort Holloway's family.

Federal prosecutors alleged that in March 2010 van der Sloot contacted Beth Holloway through her lawyer and claimed he would reveal the location of the teen's body in exchange for $250,000, with $25,000 paid upfront. During a recorded sting operation, Beth Holloway's attorney, John Q. Kelly, met with van der Sloot at an Aruba hotel, giving him $10,000 in cash as Beth Holloway wired $15,000 to van der Sloot's bank account, according to prosecutors.

Then, van der Sloot allegedly changed his story about the night he was with Natalee Holloway, prosecutors said. Van der Sloot claimed he had picked Natalee Holloway up, but she demanded to be put down, so he threw her to the ground. Van der Sloot said her head hit a rock and he claimed she died instantly from the impact, according to prosecutors.

Van der Sloot then took Kelly to a house and claimed that his father, who had since died, buried Natalee Holloway in the building's foundation, prosecutors said.

Kelly later emailed van der Sloot, saying the information he had provided was "worthless," according to prosecutors. Within days, van der Sloot left Aruba for Peru.

Van der Sloot will be held in U.S. Marshals custody until trial.

ABC News' Amanda McMaster contributed to this report.