Residents in Poland's northern city of Gdansk are voting in a by-election to choose the successor to late Mayor Pawel Adamowicz, who was fatally stabbed during a charity event.

Adamowicz's death on Jan. 14 became a platform for calls for political reconciliation but also criticism of the ruling conservative Law and Justice party.

The 53-year-old Adamowicz was a critic of the party. An attacker stabbed him onstage and then grabbed a microphone and said the act was his revenge against an opposition political party that Adamowicz had once belonged to. The attacker is under arrest.

Among the three candidates in Sunday's vote is Aleksandra Dulkiewicz, a 39-year-old lawyer who was Adamowicz's deputy and is now acting mayor. The ruling party hasn't fielded a candidate. Official returns are expected Monday.