The 48-year-old Gothenburg resident is being held on suspicion of serious industrial espionage and attempted blackmail.
Prosecutor Tomas Lindstrand indicated that documents viewed by the suspect contained corporate secrets of such a nature that they could constitute a threat to national security.
Lindstrand would not reveal how the suspect had obtained the secret documents.
Swedish Security Service Säpo’s counterespionage unit has been working in tandem with Saab in a bid to reveal the suspect’s identity.
“There have been measures in place for just over half a year to try to track this person down,” said Lindstrand.
The prosecutor said the suspect appeared to be an engineer. He has no prior convictions.
“It began with him getting hold of these documents and contacting a person at Saab. He demanded money for the secret information. It was simply a way to earn money,” said Lindstrand.
He is not believed to have received payment from anybody at Saab.
“He made demands for considerable amounts,” said Lindstrand, who would not divulge the exact sums of money involved.
It is not known whether the suspect sold the information to any third parties. Police and prosecutors refused to rule out the possibility that other people may have helped the suspect.
With 1,300 employees, Saab Microwave Systems is a leading global supplier of surveillance and radar systems for the civilian and military markets.