Sitting in a crowded Italian restaurant near Union Square, the screenwriter and director James Gray recalled the cold fear he felt while standing in a South Bronx housing project, clad in a bulletproof vest, waiting with two police officers for a known murderer to emerge from an elevator.

“I’m thinking, ‘I’m going to die,'” Mr. Gray, a native of Queens, said. “‘The guy is going to come out, he’s going to be shooting, and he’s going to hit me right in the forehead.'”

The police apprehended the suspect in the elevator without an exchange of gunfire, Mr. Gray said. That panicky night was part of his exhaustive research for a new film, “We Own the Night,” which documents the life of a family of New York City police officers during the crime-riddled 1980s. Mr. Gray participated in several ride-alongs, a program offered to civilians by the city’s police department.

The film, which opens Friday, follows the transformation of prodigal son Bobby Grusinsky, played by Joaquin Phoenix, who is a high-rolling manager of a Brooklyn nightclub and has spurned the family tradition of joining the ranks of the NYPD.

Bobby’s lifestyle is thrown into doubt when his brother, Joseph, played by Mark Wahlberg, and father, Burt, played by Robert Duvall, are marked for death by a Russian drug dealer and Bobby is forced to choose between his new life and his family.

In making “We Own the Night,” Mr. Gray said his goal was to mesh an epic storyline with realistic New York City settings and dialogue that would truly represent city police officers.

“I tried to do a procedural where the procedural isn’t important,” Mr. Gray, said. “You don’t want to stray too far from reality at all, but if its too real, it turns out like a TV show.”

The title for the film plays on a motto used by street crime units in the 1980s. In 1988, there were 196,396 violent crimes committed in New York City, according to crime reports compiled by the Disaster Center. The number of violent crimes had dropped to 83,966 in 2006, according to the statistics.

While Mr. Gray said he spoke with some police officers from that era, much of the film is based on anecdotal evidence and research. Mr. Gray pored through microfilm of newspaper clips at the New York Public Library. He even had copies of microfilm enlarged to create replicas of the New York Post, which are used as props in the film.

At 37, Mr. Gray, who grew up in the 1980s in what he describes as a “nondescript Jewish neighborhood in Flushing, Queens,” was able to touch on his memory when coming up with portions of the film.

The idea for one scene, in which a gangster shoots Mark Wahlberg in the face, is based on his memories of the 1988 assassination of a police officer named Edward Byrne, who was gunned down in similar fashion while protecting a witness in the Jamaica section of Queens.
In order to create just the right mise-en-scene, Mr. Gray began riding along with officers as long ago as 2001.

He recalls an incident in the Bronx when he accompanied several officers on a call for a domestic dispute, where a suspect, whom police believed was high on PCP, was beating up his brother. When they entered the apartment, the suspect lunged at Mr. Gray.

“The cops all had to pile on him,” Mr. Gray said. “I don’t know why he went straight for me. I was standing there with a notepad.”

It was with that pad that Mr. Gray tirelessly jotted down the lingo of the police officers he accompanied. Words such “perp,” for perpetrator, and “collar,” for arrest, became part of the dialogue in the script.

“The language stuff, I wrote it all down,” Mr. Gray said. “I tried to get all of it right.”

In the film, the police officers played by Messrs. Wahlberg and Duval converse in common NYPD lingo, which Mr. Gray says came straight from the mouths of police officers during his ride-alongs.

“It’s better to be judged by 12 than carried by six,” Mr. Wahlberg’s character says after he hands his brother a gun.

The saying, which refers to jurors and pallbearers, is a classic among police officers, a former city police officer and prosecutor who is now a professor at John Jay College of Criminal Justice, Eugene Mr. O’Donnell said.

Mr. O’Donnell fears, though, that the sayings could be used to paint police officers in a negative light. “I’ve heard cops who have never shot anybody say that line,” he said.

Unlike many Hollywood police films that depict corrupt cops, Mr. Gray’s film mostly paints police officers in a positive light.

“I wound up getting a lot of respect for them,” Mr. Gray, who still speaks on a biweekly basis with some of the officers he met during his ride-alongs, said. “It’s a daily life and death scenario.”

The director was especially influenced by an NYPD detective, Edward Conlon, and the two became friends. A Harvard graduate and son of a police officer, Mr. Conlon joined the police department in 1995. He spent several years writing for the New Yorker and in 2004 published a police memoir called “Blue Blood.”

“There are tremendous contradictions in him,” Mr. Gray said. “He’s this very bright guy who is collaring perps later in the evening.”

An e-mailed request to interview Mr. Conlon was not returned by the police department.

Even though Mr. Gray got the feeling that the police department was suspect about his motives, his film crew was able to get city police officers to serve as extras in the movie.

“They said ‘this guy is going to make something respectful,'” he said.

If the film does well at the box office, it could help in the police department’s recruiting efforts.

“We could use a positive movie about the police department, ” Mr. O’Donnell said. “At $25,000 a year they need all the help they can get.”