The Israel Police and the Shin Bet security agency are continuing to investigate Monday’s bus bombing in Jerusalem, in which 21 people were wounded. A gag order has been placed on the details of the investigation.

The nature of the attack has raised a number of questions: Where did the bomb come from? Who produced it? Did the terrorist who planted it manage to flee? Or was the unidentified man who was sitting in the seat where the bomb went off, and is now in critical condition at Shaare Zedek Medical Center, in fact the terrorist? Also, were the bus and its passengers the intended targets?

Israeli Prime Minister Benjamin Netanyahu said on Tuesday, “We will spare no effort to bring those responsible for the attack and their supporters to justice.”

Defense Minister Moshe Ya’alon said, “We don’t know yet the full details of this attack, but the systematic activities of the IDF and Shin Bet are foiling attacks on a daily basis.”

Seven of the people wounded in the attack were still hospitalized as of Tuesday night. No terrorist group took responsibility for the bombing, but both Hamas and Islamic Jihad called it a “natural response to the crimes of the Zionist occupier.” The military wing of the Mahmoud Abbas-led Palestinian Fatah faction also praised the bombing and called for more such attacks.