Rebekah Brooks brought former News of the World news editor Greg Miskiw back from his job in New York because she considered the role “a waste of money” the Old Bailey heard today.
Upon his return to London, Brooks appointed Miskew head of the news investigations unit although she said they never socialised together.
Describing Miskew, Brooks said: "He was very old school and had been there forever… that's what it felt like to me. He ran quite a tight ship. People who worked with him said he was professional and hardworking, and worked long hours.
"I really only spoke to him in the course of our work. I didn't socialise with him, I didn't know that much about him personally.
"He was quite insular, he had an air of mystery."
The jury has already been told that Miskiw has admitted conspiring to access voicemails illegally.
Jurors heard that the investigations unit was dubbed the "dark arts department", alluding to alleged illegal activity.
Brooks denied this, and said: "The investigations unit, I think, did some great stuff while I was there. I don't recognise that description."
Brooks said the investigations unit came to an end in 2001 after it quickly became apparent that it "wasn't working".
She said it was better that investigations and the newsdesk worked together, adding: " It was just better to have it all back together so we put the team back together and it worked much better."
She said she could not remember the specific date of the end of the unit, but it probably would have officially finished at the end of June 2001.
Asked about suggestions that the unit had been set up specifically to hack phones, Brooks said: "It's just not correct."
Brooks said the aim of the News of the World was to "set the news agenda rather than follow it".
That meant printing fresh news and "the story behind the story".
She said the main campaign the newspaper had run during her tenure was for Sarah's Law.
Brooks said around 200 stories made it into the newspaper out of a pool of stories twice the size.
"You would always have access to the wires, the Press Association. You would also have the news on so you were getting stories from all sorts of places."
Brooks said that, as editor, she would not have known where every story had come from.
"It's impossible for an editor to know every source for every story. Of course it's impossible with the sheer volume that's coming into the paper."
All of the defendants deny all of the charges.
The trial continues.