A Hamas-run military court in Gaza has convicted four Palestinians for their involvement in the abduction and murder of the Italian activist Vittorio Arrigoni in April 2011.
Arrigoni, 36, a pro-Palestinian activist, was murdered in Gaza by ultra-conservative radical Islamists.
He was found dead hours after he was seized by Salafist militants.
The group, which was in conflict with Hamas, was demanding the release of its leader, who had been arrested.
The Salafists in Gaza are an Islamist movement that considers Hamas as too moderate, our correspondent says.
Mahmud al-Salfiti and Tamer al-Husasna were given life sentences for Arrigoni's kidnapping and murder.
Khadr Faruk Jerim received 10 years for kidnapping and Amer Abu Ghola one year for providing the apartment where Arrigoni was found.
Arrigoni was a member of the International Solidarity Movement (ISM) and had been in Gaza for several years.
He was the first foreigner kidnapped in Gaza since BBC journalist Alan Johnston was abducted in 2007.