That means he could be released in 2016, newspaper DN reports.
Pela, who was 19 years old at the time, was murdered in Iraq, and her death became the catalyst for a large discussion in Sweden at the time about so-called "honour killings".
Two of her uncles were later convicted in a Swedish court of having been involved in the murder. Prosecutors said she was killed because she did not want to follow her family's strict rules. Her father has also admitted being involved in the murder, but has not been brought to justice.