GAZA CITY, Gaza Strip (AP) — Hamas officials say the shooter who killed a senior Hamas commander in March was a former member of the group who joined a radical al-Qaida-inspired rival and was secretly recruited by Israel.

Hamas said Tuesday it arrested 45 alleged collaborators with Israel, including three allegedly involved in killing Mazen Faqha outside his Gaza home.

It was the largest such sweep since the Islamic militant group seized Gaza a decade ago.

Hamas released a purported videotaped confession in which the shooter says he was recruited by Israel and was allegedly paid to form al-Qaida-style cells.

A Hamas official says the assailant was expelled from Hamas four years ago and joined an al-Qaida-inspired outfit. He spoke on condition of anonymity because he was not authorized to discuss the sensitive case.