JERSEY CITY, N.J. (AP) — Jersey City paused Thursday to mark the one-year anniversary of a bias attack that killed a police officer and three people in a Jewish grocery store, and shone a light on tensions between city residents and a burgeoning Orthodox community.

The ceremony was held at the cemetery where Police Detective Joseph Seals was shot and killed on Dec. 10, 2019, during a chance meeting with assailants David Anderson and Francine Graham. Seals had gone to meet an informant when, authorities have speculated, he may have stopped the U-Haul van Anderson and Graham were driving because it fit the description of a vehicle connected to the slaying of a livery car driver a few days earlier.

Seals “chose to meet the informant here by himself, because he thought it would be beneficial in getting more information and helping the broader community,” Mayor Steven Fulop said. “He chose to walk over to a vehicle he recognized that could have been involved in something else around the city. He chose to put himself in harm’s way because he thought that would keep other people safe.”

The encounter may have thrown off the pair’s plans and prevented more bloodshed. After shooting Seals, Anderson and Graham drove to the kosher market about five minutes away, where they shot and killed three people including the store’s owner, 31-year-old Mindel Ferencz; Moshe Deutsch, 24, a rabbinical student from Brooklyn who was shopping there; and store employee Douglas Miguel Rodriguez, who held the back door open for a wounded customer to escape before he was shot.

A separate commemoration for them was scheduled for later Thursday, coinciding with the first night of Hanukkah.

Seals, a 40-year-old married father of five, was lauded as a model officer who served on a special team focused on seizing illegal weapons in the city of 270,000 that sits across the Hudson River from New York City.

“You have to turn this into a positive,” Police Chief Michael Kelly said Thursday. “These folks who have given the ultimate sacrifice give us our strength. We have to continue to memorialize them and continue to let our young cops know that these sacrifices are going to be remembered forever.”

Anderson and Graham, who had connections to Jersey City but weren't living there at the time of the attacks, barricaded themselves inside the store and were killed after a lengthy gunfight with police. Authorities said notes and online posts by the pair, who were Black, reflected a hatred of Jews and law enforcement. Investigators found five weapons and hundreds of rounds of ammunition in the store afterward, and found a bomb in the couple’s van plus materials that could have made a second bomb.

Tensions flared in the days after the shootings when Black board of education member Joan Terrell-Paige wrote on Facebook that members of the Black community had been threatened and harassed to sell their homes by “brutes of the Jewish community” and went on to question whether the attackers may have had had a message to send. Terrell-Paige is still listed as a member on the board’s website.

Anderson and Graham weren't Jersey City residents at the time of the shooting but had ties to the city.

Fulop denied Thursday that the shooting was indicative of broader tensions between Blacks and Orthodox Jews in the city, and said in the ensuing months numerous events were held to bring the two communities together.

“We didn’t see any of the signs of anti-Semitism prior to this where you would think it was a broader narrative,” he said.

Rabbi Shmully Levitan of Chabad of Hoboken and Jersey City, who lives in Jersey City and said he worships at the synagogue next to the market, said relations hadn't changed dramatically in the last year but praised city officials for their efforts. He said he has helped organize events like a shabbat dinner for more than 200 people that brought together a diverse group of attendees.

“We've realized we need to be more proactive about coming together as one,” he said.