By trade, they are teachers, lawyers, taxi drivers, and students. The unpaid volunteers who patrol the city with seven-point stars and badges reading “Auxiliary Police” pinned to their lapels also are the “eyes and ears” of law enforcement in New York City.

Since 1951, New York’s auxiliary police force has worked alongside law enforcement, playing a supporting role as their counterparts make arrests and diffuse criminal activity. Yesterday, the 4,800-member corps, best known for their presence at special events and parades, mourned two of their own — Officers Nicholas Todd Pekearo and Eugene Marshalik were killed on Wednesday night in a Greenwich Village shootout.

The two officers were the seventh and eighth auxiliary officers to die in the line of duty since the corps was established. Initially conceived to support the police in cases of natural disaster or emergency, the force grew in the 1960s and 1970s.

“There was a strong drive by the Lindsay administration to promote membership in the auxiliary police,” a police historian, Thomas Reppetto, said. “Crime was a big problem and there were trying to involve citizens in fighting crime.” It was not uncommon for prominent members of New York society to volunteer, he said.

In recent years, auxiliary officers have assumed patrol duties, although some are assigned to specialty units, including emergency service, harbor patrol, transit, and vice operations.

Prior to joining the force, auxiliaries undergo 53 hours of training, and commit to working one four-hour shift a week. Many of the officers, who must be between the ages of 17 and 60, volunteer for the 4 p.m. to midnight shift after their day jobs. Dressed in dark blue uniforms much like the NYPD’s, they are armed with handcuffs and wooden batons.

The job is underscored by a sense of civic duty. An auxiliary officer in Manhattan, Seth Gilman, 28, joined the force nearly 10 years ago as a student at New York University. “I initially just wanted to do something that was helping other people,” Mr. Gilman, who is a teacher at Alfred E. Smith High School in the Bronx, said. ” In the aftermath of September 11, 2001, Mr. Gilman worked 500 hours, escorting engineers to ground zero and working the security detail in Lower Manhattan.

From a law enforcement perspective, the function of auxiliary officers is crime deterrence. “It allows for a larger presence of people in uniform,” a former police officer and a professor at John Jay College of Criminal Justice, Eugene O’Donnell, said. However, “if there’s a police incident, they are supposed to get the police.”

Working on the periphery of law enforcement as such, only six auxiliary police officers were killed in the line of duty before Wednesday’s shooting. Prior to that, the most recent line of duty death was Auxiliary Officer Milton Clarke, shot in the Bronx in 1993.

Wednesday’s shooting prompted several lawmakers to call for increased funding for bulletproof vests for the auxiliaries, including Rep. Vito Fossella and Sen. Carl Kruger. Auxiliaries must buy their own vests if they choose to wear them. “The tragic murder of these officers highlights the risk every man and woman takes when they put on a uniform,” Mr. Fossella said in a statement.

Yesterday, some officers reflected on what it meant to put on the uniform. “I think a lot of us as auxiliaries feel that if we can go out there and make sure someone can go home safely, our jobs are done,” Mr. Gilman said. “It’s going to be a hard day today and tomorrow,” he said.