A US detective who discovered Judge Brian Curtin's credit card link to a childporn website said he will testify against the judge in any impeachment hearing or inquiry.

Texas police officer Steve Nelson said he discovered substantial supporting evidence that may be of assistance in any subsequent action against Curtin.

This is likely to strengthen any attempt by the government to impeach the judge.

The detective also said that reports that Curtin accessed adult pornography rather than child pornography were not accurate. He described the website Curtin logged onto as "hardcore".