Three months after reviving a baby boy who had stopped breathing, Southampton Town police Officer Kristian LoRusso added another save to his law enforcement ledger — by administering Narcan to a man who had overdosed on heroin in the back seat of a car, police said Thursday.

The incident happened May 9 in Speonk, police said.

It was on Feb. 3 that LoRusso, responding to a 911 call placed by the elementary school-aged sister of a baby boy, went to a home in Westhampton where he revived the 1-year-old child who had stopped breathing.

In that case, police spokeswoman Lt. Susan Ralph said, LoRusso overcame some roadblocks — the child’s mother could not effectively communicate with the officer due to a language barrier; the child had no pulse, forcing LoRusso to begin “rescue breathing and chest compressions” — in order to save the baby.

In the May 9th case, police said LoRusso’s prompt actions saved the victim, identified only as a 28-year-old man who had overdosed on heroin.

Ralph said that police received a 911 call from the victim’s girlfriend at 3:41 p.m. that day reporting the man was “unresponsive” after injecting heroin.

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LoRusso responded to the scene and found the man in the back seat of a car parked along South Phillips Avenue at South Country Road.

“The girlfriend called 911, saying her boyfriend was ‘unresponsive,’ ” Ralph said.

By the time LoRusso got to the scene, Ralph said, the victim’s breathing was shallow.

Ralph said LoRusso administered Narcan and that within about four minutes the man was again breathing normally.

The man was then transported to the Peconic Bay Medical Center in Riverhead via Westhampton Beach Ambulance.

Southampton Town officers have used Narcan for about two years and Ralph said the department has found it to be “a lifesaving ally in the fight against opioid deaths.”

Before joining Southampton Town police, LoRusso spent 2 1/2 years as an officer with the NYPD.