no
No
The inital statements given by Casey Anthony were part of the investigation to find her missing child that had allegedly been taken by the nanny. She was not under arrest or a suspect in the 'kidnapping' at that time. Initially, the police were investigating a missing person.
He wasn't under house arrest.
Then the person would still be under house arrest.
He was under house arrest for 10 years until his death.
He was put under house arrest
No
No, it is a common noun. He is under house arrest. He violated his house arrest and went back to jail. It would be a proper noun if it was the actual name of a thing or place. She went to the House Arrest officer to arrange the release of her son.
It is not clear that he was placed under house arrest. He is not under house address now, as at about 1900 GMT on 30 Jan 2011 he was addressing the crowds in Tahrir Square.
Galileo was put under house arrest.
At home under house arrest
Galileo Galilei