A scathing Royal Commission report found the police had planted a bullet case.
Thomas' brother Des told Checkpoint the charges were a shock but he wouldn't say whether he already knew about them before they were made public.
"It's a shock, we've got the case here where we've been trying to fight the police to reopen the Crewe murders and solve that and they don't seem to be interested even though there's new DNA technology nowdays which could be used...
"When is Arthur going to get a break?"
He said none of the judges who have presided over Thomas' past cases have got it right and he's worried about his brother getting a fair trial.
"We haven't seen it yet have we.
"He was pardoned... by Robert Muldoon and then the commission of inquiry defied the pardon because of all the lies and the planting of evidence by police - what sort of chances has Arthur got to get a fair trial now in this sort of situation?
"These charges have only just come up haven't they, as far as the public's concerned, why didn't they clean up the Crewe murders first, 50 years, that's disgusting."
Des said he did not fully know what all the charges against his brother were.
"Who would know whether he's innocent or guilty of that, I'm not gonna go out and say that he's innocent without knowing or he's guilty without knowing, I don't even know what the charges are."
He said he hasn't spoken to his brother about them.
"I'm bloody shocked about this, this is bloody disgraceful... just before Christmas he's arrested, charges come out, it's all bloody planned to make it look bad...
"What worries me is is Arthur Thomas, Arthur Allan Thomas gonna get a fair go, is he? I doubt it."
Thomas will next appear in court in March.
-RNZ
