Just two months into his service as an auxiliary police officer, Yevgeniy “Eugene” Marshalik heard a radioed description of a man suspected of breaking into a car.

Though he was new to the department, Marshalik, 19, had a well-tuned ear for police transmissions. He had the highest score on his police tests, and one 6th Precinct leader joked that he slept with the auxiliary police guide under his pillow, the police commissioner, Raymond Kelly, said at Marshalik’s funeral yesterday.

Marshalik and his partner trailed the suspect through Greenwich Village, eventually calling in uniformed officers, who arrested him.

It was by the book for an auxiliary officer, a perfectly assisted collar.

Last week Marshalik used the same instincts when he heard a radioed description of a man with a gun. He and his partner, Nicholas Pekearo, 28, spotted the suspect and followed him up Sullivan Street, but this time the perils of policing even a seemingly safe neighborhood were hammered home when the gunman shot both of them to death.

Other officers then killed the gunman, an ex-Marine and recently fired bartender named David Garvin. He had earlier murdered a waiter, Alfredo Romero, at a pizza restaurant on Houston Street.

Yesterday Marshalik was honored with a full police funeral in Brooklyn. Pekearo was similarly mourned in Manhattan on Saturday.

“People are alive today because of the actions of Eugene and his partner,” Mr. Kelly said. Before chasing Garvin up the street, Mr. Kelly said, they stopped him at the corner of Bleecker and Sullivan streets and demanded that he drop his bag. Garvin punched Marshalik in the face, but lost the bag, which contained at least 90 more rounds and another gun.

The Police Department’s chief chaplain, Rabbi Alvin Kass, compared Marshalik to President Kennedy, describing him as a bright, idealistic man who had begun to devote his life to public service. He said Marshalik, who was a sophomore at New York University, was changed by the terrorist attacks of September 11, 2001. He watched the burning twin towers from Stuyvesant High School just six days into the start of his freshman year. After college, he wanted to go to law school and someday work as a prosecutor in New York.

Rabbi Kass quoted Walt Whitman: “I hear America singing, I hear America singing,” before saying: “But the last three days since we heard about the tragic and untimely passing of two outstanding auxiliary police officers, New York City has been crying in a bitter and anguished lament because two such special people have been taken from our midst.”

As Mayor Bloomberg spoke, he looked directly at Marshalik’s family, who emigrated from Russia 14 years ago.

“Here you come from the other side of the world for what is supposed to be the greatest country in the world, and yet some bad person takes your son’s life,” he said. “But you can’t blame America, blame New York, blame the world. Sadly there are bad people, and we just have to continue to make this world better.”

Marshalik’s younger brother, Max, and friends Jacob Feygin and Corey Ackerman also spoke. Mr. Feygin reminisced about following Black Sabbath and Iron Maiden on tour, as well as discussing Marshalik’s favorite authors, Antonio Negri and Michael Hardt.

His coffin, draped in a New York Police Department flag, was carried out and saluted by hundreds of police officers, including many from the auxiliary division.

“We are in shock,” the men’s supervisor at the 6th Precinct, Sergeant David Gechlik, said. “It’s a freak event. We’re not supposed to be dealing with such things.”

Auxiliary police are unpaid and unarmed, but they wear uniforms similar to those of police and patrol neighborhoods with a nightstick and radio. They are meant to be the “eyes and ears” of the department. The NYPD has roughly 4,500 auxiliary officers, who typically work one four-hour shift a week. Marshalik worked at least three, and also worked in as an elevator operator in Midtown as he studied for an economics degree. He was buried in Farmingdale, N.Y.