OTTAWA -- Khurram Syed Sher, a medical doctor who once performed on TV's "Canadian Idol," was found not guilty Tuesday of conspiring to facilitate terrorism -- the first acquittal at trial of someone charged under the Anti-Terrorism Act.

Sher, a doctor of pathology from London, Ont., had pleaded not guilty after he was charged along with two other men in August 2010.

During the trial, federal lawyers argued that Sher had agreed with the others to raise money, send cash abroad, take paramilitary training, make and use explosives, and scout targets in Canada.

At one point in the investigation, police covertly entered the residence of one of Sher's purported co-conspirators and seized 56 circuit boards. The Crown said the electronics could be meant for "only one thing" -- to build remote-control devices to set off bombs.

Police replaced the circuit boards with identical, non-functioning replicas.

In his decision, Superior Court Justice Charles Hackland said that while Sher, 32, probably harboured some jihadist sympathies, he was not convinced the doctor genuinely intended to join a conspiracy.

As a result, the Crown had not proven its case beyond a reasonable doubt, Hackland said.

The judge described Sher as an undoubtedly bright, but ultimately "quite naive, immature and inarticulate young man."

Speaking outside the courthouse, defence lawyer Michael Edelson said Sher will now focus on rebuilding his life, which has been in limbo the last four years.

"His career has been ended, he's lost over a million dollars in income, prestige in the community, and it's been a very, very tough four years," Edelson said.

"His family has left, he's had reduced access to his children -- it's been tragic."

Sher stood quietly behind his lawyer and demurred when asked for his reaction to the decision, saying only, "It feels great."

Crown prosecutor Jason Wakely called the judgment disappointing. "We're going to review the reasons, which were lengthy and well-considered, and we'll determine whether or not there are any grounds for appeal," he said.

Sher's acquittal follows the July conviction of Ottawa hospital technician Misbahuddin Ahmed on two terrorism charges related to the conspiracy. A third man, who cannot be identified due to a publication ban, has yet to face trial.

A graduate of Montreal's McGill University, Sher worked as an anatomical pathologist at St. Thomas Elgin General Hospital in St. Thomas, Ont., south of London.

He made international headlines shortly after his arrest when it emerged he had once performed an Avril Lavigne song on "Canadian Idol," a popular show aimed at showcasing amateur singers. He spent several years free on bail, albeit under strict conditions.

In arguing its case, the Crown said Sher had joined a homegrown group dedicated to supporting "violent jihad" by whatever means possible.

Sher testified he does not believe in violence, but rather giving back to the community.

Defence arguments painted Sher as a humanitarian who donated thousands of dollars to charity and helped with earthquake relief efforts in Pakistan. He and Ahmed -- who had known each other in Montreal -- shared a love of hockey, with Sher providing advice to his friend on fantasy league pool picks.

Federal lawyers cited evidence gathered through wiretaps of phone calls, intercepted emails and covertly installed listening devices. They played sometimes sketchy audio culled from electronic surveillance of a July 20, 2010, meeting at Ahmed's Ottawa home.

The Crown portrayed the gathering as a pivotal moment for the three supposed plotters.

Sher's lawyers characterized the visit as a friendly stopover en route from Montreal to his new job in southern Ontario.

The rambling, often disjointed meeting included discussion of jihad and selection of a group leader.

Sher testified at trial he was shocked to learn during the conversation that Ahmed had become a supporter of extremism.

In his reasons, Hackland said it was clear that Sher had not met the third man before the meeting, which stretched into the wee hours.

However, the judge did not accept all of Sher's attempts to explain away his own statements and actions.

For instance, asked during the late-night meeting whether it was better to acknowledge participation in a bombing or remain silent, Sher said, "It is better not to."

At trial, Sher said he meant it was better not to bomb anyone at all. Hackland called this an obvious misrepresentation.

Ultimately, Hackland said there was not enough proof for a criminal conviction.

The judge said it was relevant to ask whether a medical doctor with a track record of humanitarian support "would so readily sign on to a group planning potential terrorist activity in Canada without any careful consideration or reflection."