Hamas confirmed Saturday evening that Mohhamed Zawari, known to Israel's security echelon as "The Engineer," was a member of the organization's military wing, Channel 2 news reported, citing a source who spoke with Al Jazeera.
The source also confirmed that Zawari was working on a project that was developing UAVs in Gaza.
Zawari, an aviation engineer and scientist, was shot three to seven times by unknown assailants in his car near his home.
The motive behind his shooting remains unclear.
On Friday, a Hamas spokesperson in the Gaza strip, Mushir al-Masri, spoke to a Tunisian radio station, blaming Israel for the attack.
"The only agency that would benefit from the hit is the Zionist enemy," Masri stated.
"The Mossad has a history of political assassinations."
"The assassination hurts Tunisia along with the Arab people, the Palestinians could have benefited from Zawari's knowledge," continued Masri.
"The Mossad did not want an Arab expert with knowledge in this field to exist."
Shortly after the assassination Tunisia's Head of National Intelligence, Abed a-Rachman Blachag Ali announced his resignation, without specifying a reason.
State security sources have not ruled out the possibility that the resignation was due to the assassination. The sources added that the resignation came shortly after a tense meeting with Interior Minister Al-Hadi Mg'dob.
One Tunisian journalist said the killing was carried out by the Mossad, who had been following Zawari for some time, Channel 10 stated.
Earlier on Saturday the Interior Minister said that in total eight people suspected of involvement in the murder had been arrested.
It had been previously reported Friday that five suspects were arrested along with multiple vehicles, weapons and mobile devices.
According to Channel 10, the nationalities of the detainees include one suspect from the Netherlands, one from Morocco and the rest from varying European countries.
An additional report from Hungary claimed that a Hungarian citizen posing as a journalist conducted an interview with the senior Hamas operative shortly before his death. The Hungarian immediately departed from Tunisia after their meeting.
The photographer that accompanied the journalist was reportedly arrested on Saturday, in Tunisia.
Zawari, 49, lived in Syria before the outbreak of the country's civil war in 2011. He is known for his contacts with Hamas, and is credited with a number of innovations in drone technology.
Israeli officials have yet to react or comment on the report.