The suspect, Abdel Hamid Abu Srour, 19, died of his injuries Wednesday evening after he was critically wounded in the attack.
"Israel police and the IDF, 24 hours after the attack, arrested a number of suspects who are Hamas operatives in the Bethlehem area who helped plan the operation and execute it," said a statement from police spokesman Micky Rosenfeld.
Hamas said Wednesday in a statement on Hamas-run al-Aqsa TV and on the Hamas Twitter account that the bombing was conducted by a member of its military wing, Izzedine al Qassam. But the organization stopped short of a full claim of responsibility.
The Hamas statement referred to Abu Srour, a resident of the Aida refugee camp near Bethlehem, as "our son."
The latest statement came from Hamas in the Bethlehem Governorate, not from the organization's official spokespeople in Gaza, where the group is based. Hamas and other Palestinian militant groups have praised the attack, but have not claimed responsibility.
The explosion happened aboard a city bus in south Jerusalem during Monday's evening rush hour. It filled the bus with orange flames
and spewed thick black smoke into the air.
It took several hours for firefighters to put out the flames. Israeli police forensics teams were later seen working on board the charred frame of the bus.
Israeli police said Monday that 21 people were injured in the blast, a number that included Abu Srour. Other details of the investigation remain under a gag order.
"We will discover who prepared this explosive charge, we will reach those who sent them and those behind them, we will hold these terrorists accountable," Prime Minister Benjamin Netanyahu said after the attack.
The bus explosion comes after more than seven months of renewed violence between Palestinians and Israelis.
A large number of the attacks -- which have declined sharply in the past few weeks -- have been stabbings, although guns and cars also have been used. Israeli authorities have responded at times with crackdowns in Palestinian areas.
The last large-scale bus attack of this type in Israel came in 2006, when an Islamic Jihad suicide bomber set off a blast at the old central bus station in Tel Aviv, killing himself and nine victims.