The QC acting for Arthur Allan Thomas has had to issue a cease and desist email to a woman who believes he's being denied his fair trial rights.

The woman claims police are depriving Thomas of a right to a fair trial "under the NZ Bill of Rights Act" in relation to the Royal Pardon granted to him after he was wrongfully convicted of the murders of Harvey and Jeannette Crewe in June 1970.

Name suppression lapsed for Thomas who, it was last week revealed, is now facing four charges of indecent assault and one count of rape.

The allegations are historical in nature and relate to two complainants, who have automatic name suppression, and recently came forward to police.

Extensive suppression orders, however, remain and prevent the Herald from publishing further details, such as the date and place of the alleged offending.

Thomas is on bail and is next due to appear in court in March.

However, during the early hours of this morning a woman, who the Herald has chosen not to name, sent a lengthy email to many police, medical and Government officials.

It contains multiple claims, including that "NZ Crown Law and the NZ Police have failed to adhere to the minimum standards of justice to which the law must conform".

"They have failed to provide safeguards against the abuse of wide discretionary powers."

The woman claims Manukau District Court is "not an impartial court as long as those charging him from Counties Manukau Police are involved".

Harvey and Jeanette Crewe. Photo / File

Thomas's lawyer, Marie Dyhrberg QC, responded in writing to all recipients saying she was "extremely concerned as is my client to see that you are writing to people purporting to be acting on behalf of my client, Arthur Alan Thomas".

"You risk jeopardising his fair trial rights and the outcome of his prosecution. He is my client and has authorised me that I am the only person who is to authorised to deal with his current prosecution.

"Please do not take any further steps in relation to his case or under his name as you are not authorised to do so.

"I am copying the various recipients of your email so it is clear this is an unauthorised email and has no connection with or approval by my client."

She hoped to hear back from the woman to confirm she wouldn't take any further action under Thomas's name "for any reason whatsoever or in relation to his current or past cases".

When contacted by the Herald today, Dyhrberg said she was letting everybody know that she was the only person who was dealing with Thomas's legal matters.

"I know a lot of people have his interests at heart but I'm the one who is conducting his defence, so we can obviously appreciate that.

"It would be quite wrong for anybody to think that anything is going out in Arthur's name because it's not ... this is just an ordinary case that will be defended in the ordinary way.

"I think the intentions are right by people who really do care about what's happened in the past and are concerned about what's happening now but this is a case which has to be conducted within the parameters of the system."

Thomas was convicted of the murders of Harvey and Jeanette Crewe, who were shot dead in their Pukekawa farmhouse in June 1970, and dumped in the Waikato River.

He was found guilty of the killings in 1971 and again at a retrial in 1973.

But in 1979, after he had spent nine years in prison, he was granted a pardon after an investigation was ordered by then Prime Minister Robert Muldoon.

A 1980 Royal Commission of Inquiry found that a cartridge case in the Crewe's garden - said to have come from a rifle belonging to Thomas - was planted at the scene by detectives.

Thomas was granted a royal pardon and awarded $950,000 in compensation.