SAN FRANCISCO, California (CNN) -- Democratic fundraiser Norman Hsu, who failed to appear at a bond hearing Wednesday in San Francisco, was taken into custody in Grand Junction, Colorado, Thursday evening, the FBI and local police said.
Hillary Clinton's campaign says it's not keeping contributions from fundraiser Norman Hsu.
Hsu had posted a $2 million bond last Friday after he turned himself in to authorities in California on a 16-year-old grand theft conviction, a San Mateo County, California, Superior Court spokeswoman said. But a bench warrant was issued for his arrest after he failed to show up for a bail reduction hearing Wednesday.
Grand Junction police Sgt. Lonnie Chavez said Hsu became ill while traveling on an Amtrak train as it passed through Grand Junction. Amtrak officials called for an ambulance, and Hsu was taken off the train and to St. Mary's Hospital for treatment, Chavez said.
Chavez said the FBI was tipped off that Hsu may be at the hospital.
Although Hsu was still at the hospital Thursday night, he is in federal custody, Chavez said. He said privacy rules prevented him from revealing the nature of Hsu's illness.
Unless doctors decide to keep Hsu in the hospital for treatment, he is expected to face a federal magistrate judge in Grand Junction on Friday morning, FBI Special Agent Joe Schadler said. Hsu will be returned to California to be sentenced in San Mateo Superior Court in connection with his 1991 conviction, Schadler said.
Hsu had been a top contributor to Democrats, including presidential candidates Hillary Rodham Clinton and Barack Obama. But their campaigns and others said they have returned or given to charity donations from Hsu, who had an open bench warrant for his arrest in California.
Hsu came under scrutiny after news reports questioned his fundraising and revealed he has a criminal record.
Ronald Smetana, in California's office of the attorney general, said Hsu pleaded no contest in 1991 to a charge of grand theft, but never showed up for sentencing.
Smetana said Hsu was accused of bilking investors of $1 million and could have been sentenced to up to three years in prison and ordered to pay restitution.
Other Democratic candidates announced they too are purging their campaigns of Hsu's contributions, including comedian Al Franken, a U.S. Senate candidate in Minnesota; U.S. Rep. Michael Honda of California; and U.S. Rep. Joe Sestak of Pennsylvania.
In a written statement, Hsu said Wednesday he was "surprised to learn that there appears to be an outstanding warrant -- as demonstrated by the fact that I have and do live a public life."
He added, "I have not sought to evade any obligations and certainly not the law." E-mail to a friend
CNN's Ninette Sosa contributed to this report.