I notice the dad described him as a "mummy's boy who tells her everything"  ? Apparently he left out some details. I wonder why the parents seemingly did not have a problem with his sudden conversion and Twitter postings ? Granted, there was little they could have probably done. 

www.bbc.com/news/world-us-canada-30824375

FBI 'foils IS-inspired plot to attack US Capitol'

The FBI has arrested a man in Ohio for allegedly planning to attack the US Capitol in Washington in an Islamic State-inspired attack.

Christopher Cornell, 20, is charged with attempting to kill a US government officer, according to court documents.

He came to the attention of the FBI after tweeting support for extremist groups like Islamic State.

The public was never in danger during this investigation, Cincinnati Special Agent in Charge John Barrios said.

Mr Cornell's father says his son may have posted angry messages about violent jihad, but he would not have been capable of carrying out an attack.

Mr Cornell said that there was no way his son "could have carried out any kind of terrorist plot".

"He never talked about any kind of violence to me or to his mother. He is a mummy's boy, he tells mummy everything."

Twitter alias

Christopher Cornell was arrested on Wednesday morning outside a gun shop after purchasing two semi-automatic rifles and about 600 rounds of ammunition. He had long been tracked by an undercover agent.

His arrest is the second reported Ohio-based threat to the US Congress in 24 hours. On Wednesday a barman was charged with threatening to kill the Speaker of the House of Representatives, John Boehner.

Mr Cornell allegedly operated a Twitter account under the alias Raheel Mahrus Ubaydah, which came to the attention of the FBI through a confidential source in August.

The source had been co-operating with the FBI in exchange for favourable treatment in an unrelated case, court documents said.

The informant and Mr Cornell - who lives in Green Township in Ohio - first began communicating through Twitter and then through an instant messaging platform similar to Twitter, according to court documents.

"I believe we should meet up and make our own group in alliance with the Islamic State here and plan operations ourselves,'' Mr Cornell wrote in an instant message, the documents show.

During a meeting in October, according to the criminal complaint, Mr Cornell told the source he needed weapons but did not want to share details of his plan.

At a second meeting, Mr Cornell allegedly told the source they would go to Washington, set off pipe bombs at the Capitol building and shoot employees and officials there.