Jose Padilla was re-sentenced Tuesday to 21 years in prison after his original 17-year sentence was deemed too lenient. The convicted terrorism plotter was found guilty of supporting Al Qaeda and terrorism conspiracy in 2007.

U.S. District Judge Judge Marcia G. Cooke imposed the longer sentence after a 2011 decision by the 11th U.S. Circuit Court of Appeals that determined Padilla’s original sentence was not harsh enough. Cooke originally sentenced the Brooklyn native in 2008 to 17 years and four months in prison.

"He is far more sophisticated than an individual convicted of an ordinary street crime," the appeals court concluded. Padilla’s attorneys had asked for 21 years while prosecutors sought 30.

Padilla's mother, Estela Ortega Lebron, said she was relieved the sentence was not harsher and said it would be appealed.

"You have to understand that the government was asking for 30 years to life sentence in prison," she told the BBC News"This is not about Jose Padilla. This is a political case. I know that justice is going to be done on my son's behalf one of these days. It might not come today but it will come, believe me, it will."

In 2002, the 43-year-old was arrested O’Hare International Airport in Chicago on suspicion of plotting a radioactive “dirty bomb” attack. At the time, tensions were high after the Sept. 11, 2001 terrorist attacks.

Padilla was held for nearly four years as an “enemy combatant.” After pressure from civil liberties groups, that charge was dropped and his case was moved to a civilian court. In 2006, Padilla was transferred to a Miami jail to face criminal conspiracy charges and on Aug. 16, 2007, he was found guilty of conspiring to kill people in an overseas jihad by a federal jury.