A Plaid Cymru politician has been ordered to appear in court after she retweeted “highly inappropriate” comments on social media about a murder trial.

Helen Mary Jones, a Welsh Parliament MS, shared a Twitter post written by a domestic abuse campaigner which expressed “hope” that a jury would find a man guilty of murdering his wife.

The tweet, posted on Saturday and shared by Ms Jones the same day, related to the trial of Anthony Williams, 70, who killed his wife Ruth, 67, five days into lockdown, on March 28 last year.

The message, written alongside a BBC article about the trial, said: “Another perp using the ‘I just snapped’. It is complete bullshit! As so many of us will know, there would have been history of domestic abuse.

“I hope this jury finds him guilty of murder.

“Rest in peace, Ruth.”

The issue can only now be reported after reporting restrictions were lifted on Wednesday.

Ms Jones, who represents Mid and West Wales in the Senedd, is known for her campaign work for equality and social justice.

The tweet was written by Rachel Williams, a prominent anti-domestic violence campaigner and pioneer of the Ask for Ani (Action Needed Immediately) scheme, of which the Duchess of Cornwall is a patron.

Ms Williams has also been told by Judge Paul Thomas to appear at Swansea Crown Court on Thursday.

She deleted the tweet on Monday after being contacted by Gwent Police officers on the instruction of the judge.

No evidence was heard during the trial that the defendant had a history of domestic abuse.

In England and Wales, jurors are meant to deliver verdicts solely based on evidence heard in court, and told to ignore any information or commentary from external sources, including on social media.

A defendant has a right to a fair trial, and anything that creates a serious risk of prejudicing a case could lead to it being halted or scrapped.

The Contempt of Court Act makes it an offence to publish anything which could prejudice or impede a trial.

The tweet was posted after the jury in the murder trial had adjourned their deliberations for the weekend.

On their return to court on Monday, Judge Paul Thomas drew their attention to the social media commentary, saying: “It’s come to my attention that, over the weekend, there have been some highly inappropriate comments made on social media about this case.

“I should make it abundantly clear that those comments have not come from anybody connected with the case and, having been shown the contents of one such piece of social media, they clearly don’t have any idea about the evidence in this case or the issues in this case.”

The judge told prosecutor Matthew Roberts that domestic violence “is a terrible scourge”, but added that a “one-size-fits-all approach is highly inappropriate, particularly in this case”.

Addressing both prosecution and defence, Judge Thomas said: “This case will be before me on Thursday. Those involved will have to make themselves available on Thursday, and they should be told that forthwith.”

No jury members said they had seen the Twitter posts, and resumed their deliberations before finding Williams not guilty of murder on Monday afternoon.

He will be sentenced for manslaughter by reason of diminished responsibility on Thursday after previously admitting the charge.

In December, Ms Jones apologised for retweeting a post which equated discrimination faced by the transgender community with the Holocaust, which she acknowledged had “caused pain and hurt to many”.

A spokesman for Plaid Cymru said “it is not appropriate for the party to comment” about her summons to court.

Ms Williams confirmed she has also been asked by the judge to attend the court on Thursday, but declined to comment.