Former National Intelligence Agency boss Billy Masetlha has described the case against him as "a political plot by those he regarded as comrades".

There was a tad of bitterness in Masetlha's voice as he stated his opinion on the three-and-a-half year trial which unexpectedly came to an end on Thursday.

The Pretoria Specialised Commercial Crimes Court acquitted Masetlha and his two co-accused, IT expert Muziwe-ndoda Kunene and former National Intelligence Agency manager for electronic surveillance Funokwakhe Madlala, of fraud charges relating to hoax emails.

The hoax emails implicated senior ANC members in a conspiracy against the then deputy president Jacob Zuma.

"I expected this from the beginning. I knew we were not guilty.

"I knew this was a total frame-up for political reasons," said a relaxed Masetlha, who was fired by former president Thabo Mbeki in 2006.

He said the charges against him were a political ploy by those he regarded as his comrades. "It's like fighting in a trench with your comrade, who is closer than your brother. We are all fighting for democracy and transformation. And then this comrade turns away from fighting the enemy to shoot you in the back," said Masetlha, adding that he felt "betrayed and hurt".

He said these people tried to destroy him, his integrity and livelihood. He lost nearly everything, having to obtain loans to pay his defence attorney and to support his family. "I had mixed feelings when we were acquitted. I felt vindicated but couldn't jump in jubilation.

"I thought: why did I have to go through all this if it was something that shouldn't have happened in the first place?"

Regarding his former job at the NIA, Masetlha reacted: "No! I don't want that job back. Those corridors will haunt me with the betrayal I experienced."

His priority now was to pick up the pieces and get healing for him and his family.

"From here I am going to my 80-year-old mother in Soweto. As soon as I have enough money, I'll take her for counselling. This thing was very hard on her, but she kept believing in me," he said softly.

Masetlha was unemployed during the trial. He said he could not expect anyone to employ someone who was often off work to attend court proceedings and might end up in jail. So he did "business consultations and risk management and investments" for people.

His short-term future aspirations included consulting with the ANC. Masetlha made it clear it was not the party that had been against him, but only a few individuals.

Then he sat back, smiling: "I knew this day would come."