Harare - Lawyers for politician Roy Bennett have failed to stop e-mail evidence they say is bogus from being used against him at his terror trial in Zimbabwe.
Prosecutors say the messages prove Bennett had contact with an arms dealer and support their view that he plotted to overthrow President Robert Mugabe.
Bennett's lawyers say they were not allowed to challenge the messages to show how easy they were to concoct.
Bennett denies insurgency, banditry, terrorism and several other charges.
He could face the death penalty if convicted.
Bennett is an ally of Prime Minister Morgan Tsvangirai, whose Movement for Democratic Change (MDC) says the trial is politically motivated.
The case has threatened to split the unity government.
Basis of case
The e-mails are alleged to show contact between Bennett and Peter Hitschmann, a convicted arms dealer.
Hitschmann was called as a prosecution witness after implicating Mr Bennett in earlier testimony, but on the stand he said his evidence had been extracted under torture.
He denied have any contact with Mr Bennett and said the e-mails were fake.
Judge Chinembiri Bhunu said testimony obtained by torture was inadmissible, in a major blow for the prosecution case.
But on Wednesday the judge ruled that the e-mails could be considered as evidence.
"The e-mails cannot be tainted by the alleged abuse suffered by Hitschmann," Judge Bhunu said.
"They are relevant and vital to the fair resolution of the case and are hereby admitted as evidence."
Attorney General Johannes Tomana said he was happy with the judge's decision.
"Our link between Hitschmann and the accused person is in the communication between the two of them," he said outside court.
"Those e-mails are the basis upon which the state founds the connection between Hitschmann and Bennett."
In challenging the messages, defence lawyer Beatrice Mtetwa produced e-mails she said she had sent in the name of the attorney-general to show easy they were to fake. Local journalist Brian Hungwe says Mr Tomana then made unspecified threats against Ms Mtetwa.
Outside court, she argued she had been prevented from properly challenging the e-mails.
"The state is trying to stop us from showing that e-mails can be fake," she said.
Bennett, treasurer for the MDC, was due to be installed as a deputy minister when he was arrested a year ago.
