The ministry announced that it had conducted an investigation into three possible causes before arriving at their conclusion: a Hamas test rocket hitting the boat, the direct targeting of the boat by Israel and an accidental explosion by Israeli equipment left in the sea.
The investigation allegedly found that the boat carrying the fishermen was "completely outside the range of the rocket fire" and that eyewitness testimony and footage excluded the possibility that Israeli forces had targeted the boat.
The investigation found that about half an hour before the explosion, two other fishermen found an Israeli quadcopter in their nets and handed it over to Maritime Police. An explosive device was found attached to the quadcopter, the Gazan Interior Ministry claimed. Another quadcopter was allegedly found in the fishing net of the three dead fishermen and was found to be "completely identical" to the one found by the other fishermen.
The forensic report on the three fishermen found that they were killed by a severe explosive shock by a non-fragmentation device, as no metal fragments were found in their bodies. The explosive device reportedly found on the other quadcopter matched this description.
The Gazan Interior Ministry released an animated video simulating the incident.
The Hamas-run ministry stated that it holds Israel "fully responsible for the killing of the three fishermen."
"We call on all international institutions and bodies to work to provide protection for Palestinian fishermen in the sea of the Gaza Strip, who are constantly exposed to the assaults and violations of the Israeli occupation," said the coastal enclave's Interior Ministry, according to Palestinian media.
The IDF stated on Sunday that it was not responsible for the incident and that it seemed that the deaths were caused by an internal incident in the Gaza Strip. A Hamas rocket test towards the sea was reportedly conducted shortly before the explosion.