JERSEY CITY, N.J. (CBSNewYork/AP) — A Jersey City police officer will be disciplined, after allegedly posting information online about possible gang retaliation after police shot and killed a man who murdered a fellow officer.

As WCBS 880’s Marla Diamond reported, Jersey City Mayor Steven Fulop and Public Safety Director James Shea said rumors of more violence crop up frequently when a police officer is shot.

“We have had, in the past, allegations of potential retaliation against police officers but that is a fairly common occurrence and we haven’t been able to attach any credence to it,” Shea said.

In this case, the mayor said a Jersey City police officer posted a false notice online saying Bloods gang members were targeting police in connection with the shooting that killed cop killer Lawrence Campbell, 27.

The officer will be disciplined, Fulop said.

Following the report about possible gang retaliation, Jersey City police stepped up patrols, and also ordered that all officers must patrol in pairs. Port Authority and New Jersey State Police who work in Jersey City also warned their officers.

Jersey City police Officer Melvin Santiago, 23, was ambushed Sunday as he responded to an armed robbery call at an all-night Walgreens, authorities said.

Police said Campbell stole a security guard’s gun and shot Santiago at close range, killing him. Other officers returned fire, killing Campbell.

Fulop also said Wednesday that Santiago will be posthumously promoted to detective. He will also be given the department’s Medal of Honor, Fulop said.

Jersey City Police Officer Melvin Santiago was killed in the line of duty July 13, 2014. (Credit: WLNY-TV)

Jersey City Police Officer Melvin Santiago was killed in the line of duty July 13, 2014. (Credit: WLNY-TV)

“This honor will be a lasting tribute to the ultimate sacrifice paid by Officer Santiago,” Fulop said in a statement. “It is fitting and right that we honor and recognize him for his bravery and dedication to the police department and the people of Jersey City.”

New Jersey Gov. Chris Christie called Santiago “a hero and a true role model” and ordered all state buildings to fly flags at half-staff on Wednesday.

Days after the shooting that killed Santiago, second police-involved shooting happened Tuesday morning when an officer shot a man who authorities said attacked him and his partner with a sharpened fence post. The man, whose name was not released, was taken to a hospital.

Fulop said community relations are “in a sensitive place right now” and said “we’re being careful.”

“We’re talking to police as well as residents to make sure people feel safe and at the same time creating a fair balance,” he added.

While shootings are down in Jersey City, statistics show murders are up. In 2013, 20 were reported. Half way through 2014, the city is already at 15.

“I walk around with mace or I am with my brothers because the violence here, it is ridiculous,” said resident Cassandra Montanez.

Officers from Jersey City and surrounding towns showed up Tuesday afternoon to relocate memorial items from the site where Santiago was fatally shot to the nearby West District precinct, where he had been assigned.

West District Commander Capt. Michael J. Kelly said condolences have been pouring in from departments across the region. He described Santiago as a quiet, serious young man who had dreamed of being a police officer since childhood and who had just started to hit his stride after less than a year on the job.

A memorial for Campbell in the neighborhood where he lived was taken down Tuesday after Fulop said he ordered it be removed Monday night.

The makeshift collection included balloons, candles, empty liquor bottles and messages from friends scrawled on T-shirts taped to a brick wall. The messages included “thug in peace” and “see you on the other side.”

“I am not going to let a few residents pretend like they express the views of a great city like Jersey City,” Fulop said.

Angelique Campbell, Campbell’s widow, said she doesn’t plan to restore the memorial to him.

She said that Campbell had slipped back into an old drug habit over the past couple of weeks and “got back with the wrong crowd.”

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