(CNN) -- Opponents of Venezuelan President Hugo Chavez are questioning the arrest of a medical doctor accused of leaking state secrets.
Ana Maria Abreu de San Miguel, 51, was arrested last week for allegedly sharing state secrets. The public ministry announced the arrest on Monday.
The government did not specify what secrets Abreu allegedly leaked, but said it happened between 2010 and 2012.
"This is a case that shows the arbitrariness of the Venezuelan justice system in this regime," the doctor's attorney, Theresly Malave, told CNN affiliate Globovision.
Abreu is the sister-in-law of Rocio San Miguel, a vocal Chavez critic.
The announcement regarding the arrest made no mention of the health condition of Chavez, who is battling cancer.
The public ministry's release only states the potential sentences for the allegations against Abreu, without naming the allegations themselves. Revealing political or military secrets affecting state security is a crime punishable by seven to 10 years, the ministry said. The punishment is more severe if the leaked information causes diplomatic problems between Venezuela and other countries, the ministry said.
Finally, the sentence can be even longer if the secret information was obtained through one's position as a government employee, the ministry said.
Malave said that her client was a lower-level government employee who worked mostly with the needy, providing them with prescriptions. Abreu's office is not inside the presidential palace, and she has no access to the palace, or the military or anyone who may hold state secrets, the attorney said.
She said that Abreu was targeted because her relative is a fierce Chavez opponent.
"Just because Dr. Ana Maria has the last name San Miguel doesn't mean she's working there, trying to obtain secret information," Malave said.
By not revealing what secrets the doctor allegedly stole, it is impossible to mount a defense, she said.
The country's presidential campaign season officially kicked off this week.