Seals, a husband and father of five children, had been with the department since 2006. He came out of Jersey City's South District, one of the busiest police precincts in the state.
He was promoted to detective in November of 2017 and was assigned to the city's cease-fire unit.
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The wake for Detective Seals will be held Monday from 2 p.m. to 7 p.m. at McLaughlin Funeral Home on Pavonia Avenue in Jersey City.
Funeral services will be held Tuesday at 11 a.m. at Saint Aedan's Church on Bergen Avenue in Jersey City.
The 40-year-old North Arlington resident was a leading police officer in removing guns from the street, and authorities say dozens and dozens of handguns were removed from the street under his watch.
"We believe he was killed while trying to interdict these bad guys on Garfield Avenue," JCPD Chief Michael Kelly said.
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Seals is believed to be the 35th Jersey City police officer killed in the line of duty.
"It's a tough day for Jersey City," Jersey City Mayor Steven Fulop said. "Joe is somebody who is involved in the city, who officers in other precincts knew who he was, because he was a good cop."
In addition to his work with the illegal guns unit, Seals was cited for heroism in a Christmas Eve 2008 incident in which he and another officer burst through the window of a home and stopped a sexual assault that was being carried out against a 41-year-old woman.
"We cried with the family," Fulop said. "It's the hardest thing you ever have to see. No one expected Detective Seals not to return home. I'm sure his children expected him to return home."
Seals used to work at the Hudson County Jail and currently had a second job in the flooring business to help support his family.
But his dream was always to be a police officer.
"He was an excellent family man," neighbor Joe Vuocolo said. "He loved his children, did everything with them. He was a hard worker."
A number of neighbors on the officer's block in North Arlington turned off their Christmas lights Tuesday evening out of respect.
The Jersey City Police Officers Benevolent Association has set up an official GoFundMe page in support of the Seals family. The State Police PBA is also warning potential donors to be aware of fake sites that may claim to be the same thing but are actually scams.
(The Associated Press contributed to this report.)
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