A man described by the Australian Federal Police (AFP) as being the leader of the notorious international hacking group LulzSec says the AFP's claims are based on a single joke Facebook message.

A 7.30 investigation has found a teenage accomplice was actually responsible for the hack and was raided by police but never charged.

Late last month 25-year-old Matthew Flannery was sentenced to 15 months' home detention when he was convicted of five hacking charges.

When he was arrested in April last year police called him a self-described leader of LulzSec, a claim that shocked Flannery when he was bailed.

"I went to a computer in the library because, you know, they'd taken mine, and I started Googling [sic] and to my shock and horror I found that not only was I being reported by Australian news agencies, but also internationally," Flannery told 7.30.

Matthew Flannery was arrested by Australian Federal Police in April. ( ABC News )

A detailed examination of his court documents showed only one reference to LulzSec, which Flannery said was a joke Facebook message to his friend.

"I would like to know if that is solely what they are basing their claims off of and, if so, then why did the AFP - in a press release in front of the world - state that I had made claims in online chat communities that were frequented by LulzSec members that I was the leader of LulzSec?" Flannery said.

The AFP's national manager of cyber crime Commander Glen McEwen said police were unsure if Flannery was ever a member of LulzSec but his boasting attracted the attention of police.

"That's something I cannot confirm," Commander McEwen said.

"As you'd appreciate, the virtual world and the anonymity as such, people come together for certain reasons and move away.

"I cannot categorically say that the individual was part of LulzSec but I definitely can't discount that."

Commander McEwen said he did not back away from his comments that Flannery was a risk to Australian society.

"I don't make any excuse or apologise for the activity of the AFP in relation to this matter," he said.

AFP National Manager of Cyber Crime Commander Glen McEwen says he stands by the decision to charge Flannery. ( ABC )

Secret internet chat logs also show the hack announced by the AFP was carried out by a teenage accomplice.

It involved placing an offensive image on the Narrabri Shire Council website in the early hours of the morning.

Hacking sources said Flannery asked for the hack to be carried out because, far from being the leader of LulzSec, he lacked the technical skill to carry out a basic attack.

"Why were people raided as a result of my arrest - because they were associated with me? Why were they raided?" Flannery asked.

"And saying this serves no benefit to me, it's more a question of the AFP's integrity.

"Why were those people raided and arrested for much more serious offences and yet saw no charges or any kind of media attention whatsoever?"

Commander McEwen likened virtual crimes to break and enter and robbery and said the AFP stands by the arrest.

"I still don't understand where people believe that breaking in and stealing from others is harmless fun," he said.

"I'm sorry maybe I'm old school, but I just don't agree with that."