Eleven Chinese witnesses sought in connection with the birthing center case are not of used to prosecutors anymore because their credibility was "destroyed" after they jumped bail and fled to China, Assistant US Attorney Charles E. Pell said on Wednesday.

Federal arrest warrants for the witnesses were issued earlier this month on charges including visa fraud, obstruction of justice, and contempt of court for leaving the United States after being ordered to remain in the country as material witnesses.

"Because they violated the court order, their credibility is destroyed, so we would not use them anyway," Pell told China Daily on Wednesday.

All of the defendants are considered fugitives now, and they face maximum sentences of 25 years each if convicted of making false statements on a visa application, and five years for obstruction of justice, according to an earlier press release from the US attorney's office in Los Angeles.

The defendants tried to remedy their alleged misconduct by collecting evidence in China for use in the US case, Jing Wang, a lawyer representing three of them in Los Angeles, told China Daily earlier.

However, the prosecutors motioned to remove them as material witnesses. A final decision is expected to be made at a hearing in two weeks, Pell said.

Ken Z. Liang, an attorney in Irvine, California, who represented a birthing center or so-called maternity hotel called Youyun and two of the defendants, said the case would not make any progress with the absence of the 11, according to a report on Tuesday in World Journal in China.

Pell refuted those comments, saying "It's not true."

"The investigation is continuing without them," he said, without disclosing further details because "the investigation is still ongoing".

"But what I can tell you is this is a federal criminal investigation Maybe they [the lawyers] don't understand how federal criminal investigations work," he said.

Liang was not available for comment by press time.

In early March, US Immigration and Customs Enforcement agents raided 37 birthing centers in Southern California to collect evidence of alleged visa fraud and tax fraud.

Twenty-nine Chinese individuals were previously designated by US magistrates as witnesses. They would be called to testify against business operators who allegedly helped women come to the US on fraudulent visas in order to give birth to children who would become US citizens. In exchange, the witnesses would be granted immunity from prosecution.

However, 10 of them jumped bail of $5,000 apiece and fled to China early last month. Another one who returned to China was charged only with visa fraud because she had not yet been declared a witness.

Losing the status of witnesses would put the defendants in an adverse situation, Wang told China Daily in an earlier interview.

They would face arrest in the US, though their children were free to return as US citizens, she said.

liazhu@chinadailyusa.com