The domestic intelligence agency, PET, has come under fire for withholding, for over a year, a potential alibi for one of five men currently on trial for politically motivated terrorism.

The prosecution alleges that the man left through his backdoor on his way to participate in an arson attack against the Greek embassy in 2011 after he was not registered leaving his front-door by PET agents that were monitoring him.

PET neglected to inform the prosecution, however, that it had also installed video surveillance of the man’s backdoor, and that the footage from that camera does not show him leaving.

“You can only wonder why PET has sat on a piece of evidence that would give a person an alibi,” Hanne Reumert, defence lawyer to one of the accused, told DR News. “It makes me worry that maybe PET is withholding more in this or in other cases.”

According to Reumert, the new piece of evidence will have a huge impact on the trial.

“It’s a strong alibi that shows he was not at the scene of the crime at the time,” Reumert said.

The five men are charged under anti-terrorism legislation and could receive life in jail. They are accused of starting, and attempting to start, fires at a range of targets around Copenhagen, including a police academy.

The men are all connected to left-wing groups in Copenhagen and the prosecutor is alleges that the attacks were all politically motivated and so can be considered acts of terror.

According to reports, police found a logo spray-painted beside the door of the Greek embassy, which was set on fire using a napalm-like fluid but was quickly put out by passers-by.

The logo is that of a Greek anarchist movement called Conspiracy of Fire Cells that the prosecution alleges inspired the defendants.

Police found that internet searches for Greek anarchist groups were made one of the accused's computers.