Norman A. Carter Jr. says he was the type of cop who spoke up over the deafening blue silence during 25 years as a Philadelphia police officer.

Cops don't rat on each other - not if a cop sees another cop "take a note," or bribe; not if a cop learns that another cop is working for the leader of a theft ring; not if a cop sees another cop bragging about transporting a drunken suspect in the trunk of a squad car.

In Carter's recently published memoir, The Long Blue Walk, he writes vividly about the emotional scars he received from clashing with, and trying to expose, corrupt fellow cops and supervisors during his years on the job, from 1967 to 1992.

Many of the problems, he writes, resulted from cops wanting to go along to get along. The blue wall of silence protected the crooked and punished the vocal.

"Peer pressure will often trump common sense," writes the 71-year-old African American retired cop. "This was why cops, just like crime organizations, protected their own by keeping their mouths shut. If you want to be a part of 'the team'; if you want to feel safe and know that you have support in dangerous situations; if you want to feel secure in your job and not have supervisors and commanders harass you; then you keep your mouth shut no matter what indiscretion you witness or hear about other officers."

Now living near Atlanta with his third wife, Carter says police-community relations are strikingly similar to what they were in the late 1960s and early 1970s: police getting "assassinated," police shooting civilians, police winding up in reportage about corruption and brutality.

The big difference, he says, is that social media amplify bad behavior.

"It seems as though we are experiencing the same thing over again and that the internal system hasn't changed," he said.

In the book, Carter recounts learning that mobsters connected to Philadelphia Mafia boss Angelo Bruno were "untouchable"; how it was the norm for police officers to "take a note" from those engaged in street crime; and how the department routinely underreported serious crimes such as rape and auto theft by coding them as lesser offenses.

He says his refusal to take bribes resulted in his being branded an outsider from his rookie days in the 14th District, and resulted in his being assigned grunt work that included having to help pick up stray dogs and walking remote beats.

"I was a certified threat to the status quo," writes Carter, who devotes many pages to his quest to bring down the late Rocco "the Godfather of Manayunk" Barba, a Main Street restaurateur who ran a theft ring aided by an officer in the Fifth District, which includes Manayunk, Roxborough, Andorra, and Wissahickon.

Higher-ups repeatedly rebuffed Carter's attempts to arrest Barba in the 1970s despite evidence he had gathered while assigned to the Fifth District that Barba's gang was burglarizing Manayunk businesses, he said.

As a result, Carter wrote, his supervisors retaliated by fraudulently charging him with failing to salute a superior, failing to wear his hat while outside his car, and violating sick-leave policy. In addition, he was assigned to foot beats in freezing temperatures that no one else had ever walked.

Eventually Barba was arrested and sent to prison, but Carter got no credit.

Although his recollections are from a different era, he says he believes his cautionary tales are timely and should be read by Philadelphia's newest police recruits, veteran cops, and top brass.

He's sent letters and copies of the book to Police Commissioner Richard Ross and to every member of City Council, he says, but has not heard back from any of them.

"Not a thank-you, not a 'What is this rubbish?' " he says.

That's too bad, Carter says, given that the blue wall of silence is still intact here, as it is in other places.

"That's part of that ingrained 'us against them' defense mechanism within the Police Department, and it's very, very powerful," he says.

Just as powerful, he says, are racist attitudes some white officers harbor about the black citizens they are charged with serving and protecting.

Racial tensions were high between the city's black population and its predominantly white police department when Carter's blue walk began.

"What I found in my short career was that many Caucasian police officers feared interaction with African Americans. They viewed African Americans as an overly sensitive, ignorant warlike people. Obviously, they watched too many Tarzan movies," Carter writes.

He laments that between media reports and his contacts within the department, it is impossible for him to deny that such views are still held by too many white officers today.

"When you don't understand a community, you don't take the time to be an active part of that community and your only reference is word of mouth from other people whose views are probably tarnished," he says. "You continually take a defensive posture whenever you interact with that community. Your every interaction has the potential for being violent."

Carter, who grew up in the 2200 block of Harlan Street in North Philadelphia, joined the police force in 1967 after a stint in the Army. He retired from the police force as a corporal.

"I thought that [becoming a police officer] would give me an opportunity to be a part of a progressive change towards equal treatment for all citizens regardless of their religion or country of origin," he writes.

Despite all that he went through, Carter capitalizes the "P" and "O" in "police officer" throughout his book because, he says, he is proud to have been a cop. The father of five adult children says he never regretted his career choice.

"The police department should never be looked upon as your adversary," he said. "We should be looking at the police department as someone who is in league with us to make things better."