The police officer shot and killed as part of a multiple-location shootout in Jersey City on Tuesday was identified as a 15-year police veteran, according to law enforcement officials.

Det. Joseph Seals was the first person identified as a victim of two suspects who started the gunfire just after 12 p.m., Jersey City Police Chief Michael Kelly said at a press conference. Seals was a 39-year-old father of five who had joined the Jersey City Police Department in 2006, reports NBC News .

The detective worked with the city’s Cease Fire Unit and was the department’s leading officer in removing guns from Jersey City streets, Kelly said.

Related: Officer, 5 Others Killed in New Jersey Standoff

According to senior law enforcement officials, Seals saw a U-Haul truck possibly linked to a murder from over the weekend in Bayonne. As he approached the truck, one of the suspects got out of the car and shot him.

Seals died from his injuries.

The suspects then drove the vehicle to a kosher market where three people were killed.

Jersey City Mayor Steven Fulop said at a news conference on Wednesday morning that security footage showed the shooters traveling slowly through the streets in a U-Haul van on Tuesday, stopping outside the store armed with long guns and immediately opening fire, reports NBC News .

Three civilians were found dead inside the store following what became an hourslong standoff and shootout between police and the suspects. The two suspects were also found dead. Two officers were reportedly injured in the exchange of gunfire.

One of the two suspects had a social media page containing anti-Jewish and anti-police writings, officials and sources said Wednesday. But Public Safety Director James Shea emphasized that the shooters' motive is not yet clear and is under investigation.

Shea told reporters Wednesday that police in the area responded to the store immediately, probably saving more people from being killed.