James Holmes
James Holmes on trial for the Aurora cinema murdersReuters

Three jurors have been dismissed by the judge in the murder trial of Colorado cinema shooter James Holmes on the basis that they were tainted by a prosecutor's message on Twitter.

According to Reuters, District Attorney George Brauchler sent a tweet about a videotaped interview of Holmes conducted by a psychiatrist. In 2012, 27-year-old Holmes killed 12 movie-goers and injured 70 when he began shooting in an Aurora, Colorado cinema.

The California native pleaded not guilty by reason of insanity to multiple counts of first-degree murder, attempted murder and explosive charges, Reuters reported. Holmes's attorneys claim he suffers from schizophrenia.

Jurors in the trial had been advised by Arapahoe County District Judge Carlos Samour to not read media reports or materials on social media about the trial. Samour also ordered jurors to not discuss the case between themselves or with others.

"Clearly there's been a violation of my advisements," Samour said when he dismissed the jurors.

The tweet was brought to the judge's attention on Friday (5 June) but Holmes's defence lawyers. Reuters reported that Brauchler has since apologised for the tweet.

Samour said the court received notice about the tweet from a juror, who he then spoke to. The female juror reported that a fellow juror had mentioned the tweet on Monday and that two other jurors has heard the discussion.

The problem with tweeting

The female juror said her fellow jurors discussed the tweet and details about the case that did not occur in front of the jury on the patio outside of the jury room, NBC News reported.

The judge spoke to all three jurors involved, dismissing all jurors involved except for the juror who reported the incident.

NBC News reported that the three jurors dismissed were Juror 872, a white woman in her 20s or 30s with three kids; Juror 412, a white woman in her 20s or 30s who works in information technology for a mental health company; and Juror 495, a white woman in her late 20s to early 30s. The juror who reported the incident was identified as Juror 673.

Reuters reported 24 jurors have been chosen for the panel hearing evidence in the trial that began in late April. Judge Samour has not revealed who will be part of 12 person jury to decide the case.