A “significant” piece of new evidence has come to light that could “potentially imperil” the planned start date of the Claremont serial killings trial.

At a case management hearing in the Supreme Court this morning, prosecutor Carmel Barbagallo said she had to be careful about what she said about the item as not to compromise further inquiries.

However, as Bradley Robert Edwards listened intently from the dock, she did reveal the item was a piece of clothing obtained from a Telstra worker from the 1990s.

Asked by Justice Stephen Hall if the item was linked to Mr Edwards – who worked for Telstra at the time — Ms Barbagallo said it was “utilised by technicians at that time”.

Camera Icon Prosecutor Carmel Barbagallo. Credit: The West Australian, Daniel Wilkins

The court was told the item was being analysed so that fibres from the piece of clothing could be compared with other fibres in evidence, and Ms Barbagallo foreshadowed a report may not be complete until mid to late June.

Justice Hall said he was concerned the new inquiries may jeopardise plans to start the nine-month trial – which has been billed as the biggest trial in WA history – on July 22.

Mr Edwards is accused of abducting and murdering Sarah Spiers, Jane Rimmer and Ciara Glennon from the streets of Claremont in the mid-1990s.

He is also due to stand trial over an alleged sex attack on an 18-year-old woman in Huntingdale in 1988 and the rape of a 17-year-old in Karrakatta cemetery in 1995.

“This is potentially going to imperil the start of this trial,” Justice Hall said. “It’s looking increasingly in danger of not occurring.”

Camera Icon Don Spiers leaves court. Credit: The West Australian, Daniel Wilkins

Ms Barbagallo said investigators were “doing what they can” and were “acutely aware” of the impending trial.

“They are doing what they can as quickly as they can, ensuring they don’t make any errors in the process,” she said.

Ms Barbagallo said the evidence had only come to light in the “last short while”. Asked by Justice Hall how, Ms Barbagallo said police were continuing to talk to people and follow lines of inquiry.

“The police are damned if they do, damned if they don’t,” she said. “They are doing what they are tasked to do.

Camera Icon Defence lawyer Paul Yovich arrives at court. Credit: The West Australian, Simon Santi.

“The potential of this evidence, we say, is quite significant.”

Defence lawyer Paul Yovich said Ms Barbagallo telephoned him about the piece of clothing on Wednesday, and received a preliminary report about the item yesterday.

He said the defence’s fibre expert estimated they would need eight to 12 weeks to consider the final report.

He said the defence fibre expert lived in the UK and may need to fly to Perth to view the item.

Asked by Justice Hall whether he had an extension of aid from Legal Aid to cover the cost, Mr Yovich “not yet” but said the organisation had been “very good about our requests”.

“I can say with complete confidence, there is no way we will be able to finalise and disclose our material before the trial date,” he said.

Justice Hall said: “That seems perfectly apparent.”

Justice Hall said as “unsatisfactory as the situation is”, he left the trial to start on July 22, saying he was “fully recognised it may be necessary” to change the date.

Mr Edwards is due back in court on June 18 and 19 for a directions and case management hearing.

Outside court, Ms Spiers’ father Don, asked if it was frustrating hearing that the trial could be delayed, said “that’s the process, that’s to be accepted.”