The prosecutors have offered no motive for why Andreas Lubitz, 27, would take the controls of the Airbus A320, lock the captain out of the cockpit and deliberately set it veering down from cruising altitude at 3,000 feet per minute.
German police have searched his home for evidence that might offer some explanation.
Robert Tansill Oliver, a Jehovah's Witness, lost his 37-year-old son Robert Oliver Calvo in the Germanwings plane crash.
"I don´t feel anger. I'm really sad for the parents of that young pilot. I mean, I can't imagine what they´re going through right now. As well as companions here, they are all feeling, hurting. No we don´t feel anger at all. As Witnesses we are peace makers. We are sorry it happened of course. We blame what the bible calls the rule of the world. We are angry with the ruler of the world," Oliver told reporters outside the Rey Don Jaime hotel where the relatives of the victims are staying.
Oliver was not keen on launching legal action over the loss of his son.
"I'm in touch with the American Embassy in Madrid and the consulate in Barcelona it all depends on how well things take place. The generalitat now is intervening and giving a certain amount of counsel, guidance. We have to just wait and see. We´re not eager to take any legal action. We're mostly interested in sharing hope and comfort and of course being with our family, our niece and our grandchildren, comforting them," he said.
"The responsibility of the governments and the airline companies, I hope they do take steps to make sure what happened to my son never happens again to anyone," Oliver added.
Robert Oliver Calvo was a Barcelona-born American citizen.
He worked for the Barcelona-based clothing company Desigual, and left behind a wife and two children.
Lufthansa subsidiary Germanwings could face liabilities well above the typical ceiling in airline crashes for the passengers who died on Tuesday, some aviation lawyers said.
A lot will depend on whether the airline can defend itself against negligence claims.
An international agreement generally limits airline liability to around $157,400 (£105,734) for each passenger who dies in a crash if families do not sue, but if families want to pursue compensation for greater damages, they can file lawsuits.
Lawyers who have represented families in past airline disasters said on Thursday that potential lawsuits could focus on whether Germanwings properly screened the co-pilot before and during his employment, and on whether the airline should have had a policy requiring two or more people in cockpits at all times during a flight.