Faced with persistent problems in heroin-overdose deaths, many involving the dangerous additive fentanyl, NYPD detectives are tracking each fatal incident in an effort to go after the traffickers, a top police official said Tuesday.

Cops are drilling down into each heroin death and seeking to arrest major traffickers who smuggle the narcotic through Mexico, as well as street sellers involved in drug-gang retail operations.

Fueling the urgency is the widespread presence of fentanyl, a synthetic opioid that is 50 to 100 times more potent than heroin, said NYPD Chief of Detectives Robert Boyce.

“Fentanyl is the issue, that is the additive, that is what is driving the overdoses,” said Boyce, adding that the synthetic opioid dangerously boosts the purity of street heroin — already at 60 percent pure.

Boyce’s assessment came at a monthly crime briefing attended by Mayor Bill de Blasio and NYPD Commissioner James O’Neill where police reported another record month drop in crime in crime, making October 2016 the safest October in the modern CompStat era of record keeping.

With 500 heroin deaths in the city so far in 2016, cops are teaming up with the city’s five district attorneys, special narcotics prosecutors and Manhattan U.S. Attorney Preet Bharara to prosecute dealers who sell potent heroin.

While complete 2016 data isn’t available, officials said that since July 1 almost half of all drug-overdose deaths involved fentanyl. In 2015, the city experienced 556 heroin overdoses, and out of a total of 937 drug-overdose deaths 146, or 16 percent, involved fentanyl, city statistics show.

On another issue, the Aug. 2 killing of Howard Beach jogger Karina Vetrano, Boyce said that despite three months elapsing detectives are still approaching the case with “a sense of vigilance and endurance.”

“They know this case is going to be a tough case,” Boyce said. “Here is a group of investigators who solve some major crimes in a couple of days. Those thing happen. But these things [Vetrano case] happen as well. There is not a day that goes by when we don’t get a tip, or two or three.”

Each tip is vetted and checked out, Boyce said. Vetrano, 30, was found strangled and sexually assaulted the night of Aug. 2 in the Spring Creek Park area near her Howard Beach home. An avid jogger, Vetrano had gone for a run. When she didn’t return home, her family contacted police.

While some Howard Beach residents have privately voiced frustration at the lack of an arrest, Boyce remains optimistic.

“We will continue until we make an arrest in this case, which I know we will,” he said.