Week after week, racist posts appear on Thee Rant, a blog for current or former New York City police officers: African Americans are called “apes;” a retired officer says one of the blessings of retirement is not having to work the Puerto Rican Day parade, with its “old obese tatted up women stuffed into outfits that they purchased or shoplifted at the local Kmart store;” a Middle Eastern cab driver berated by an officer is termed a “third worlder” who should have his “head split open.”

And week after week, the department’s top officials are, at once, embarrassed and powerless.

“It’s very disturbing stuff. Outrageous stuff,” said Stephen Davis, the chief spokesman for the NYPD. “We see it. It’s a problem.”

At the heart of the problem are the limits the department faces in what it can do.

“Monitoring these things is challenging,” Davis said. “There are privacy issues involved. We can’t go and peel back email names and tags and try to find out who these people are.”

The issue of the blog, started by former NYPD officer Ed Polstein in 1999, has gained notoriety most recently after a white South Carolina police officer shot a black man to death. Shortly after a video of the officer appearing to shoot the fleeing man in the back went viral on the Internet, Thee Rant blew up with comments.

“Cop looked good in his stance,” read one post.

Polstein, who did not respond to requests for an interview, has said previously that anyone wishing to post on the blog has to provide proof that they are a current or former member of the NYPD. But whether they are, and how many have signed up, are among the many mysteries surrounding Thee Rant. The blog says it garners 120,000 page views daily.

Leonard Levitt, a respected former Newsday reporter who runs the website NYPD Confidential, said he has stopped assigning much significance to Thee Rant.

“To be honest, I don’t read it,” Levitt said. “I’d say these guys represent the worst elements of the department. I don’t think they speak for the average cop. I have a feeling it’s four or five guys doing most of the yowling.”

Incidents of officers being investigated or punished for their behavior online, in social media or on personal cell phones, have cropped up in Illinois, Missouri and Florida in recent weeks and months.

In a St. Louis suburb, for instance, an officer was fired after posting racist remarks about the protests in Ferguson. In San Francisco, eight officers were fired for exchanging racist and homophobic text messages.

Relations between the police and minorities have been fraught in New York for decades. The assault on Abner Louima and the killing of Amadou Diallo during Rudy Giuliani’s administration sparked a rise in tension. The aggressive stop-and-frisk tactics during Michael Bloomberg’s mayoralty deepened the mistrust and anger. And the choking death of Eric Garner on Staten Island last year provoked protests and slogans.

William Bratton, Mayor Bill DeBlasio’s police commissioner, has acknowledged the poor relations and vowed to improve them.

The existence of Thee Rant, and the occasional, perhaps outsize attention it gets, has not made Bratton’s efforts easier.

Garner’s death prompted some of the more extensive back and forth on the blog. Garner was killed when an officer sought to subdue him during a stop for illegally selling loose cigarettes. Bratton initially said it appeared the officer had used an improper chokehold. But a grand jury on Staten Island declined to indict the officer.

On Thee Rant, support for the officer was substantial. And occasionally ugly.

“A more accurate headline would be "Non Compliant Fat Bastard Gets Just Due In Resisting Law Enforcement Officers,” read a post in reaction to headlines in the city’s papers.

“Yes, they’ll pay off the 'family,'” started another. “It’s a lot cheaper than a riot…And therein lies the problem...The cities of America are held hostage by the strong-arm tactics of the savages.”

Davis, the NYPD spokesman, said department policy is that officers should not be on social media, as well as blogs, except for official business. The department has shown it is willing to act against problem officers when it can. In 2012, New York City police officers were disciplined over racist and violent comments made on Facebook, many of which targeted the annual Labor Day West Indian Parade, describing the event as a “scheduled riot” and comparing it to working at a zoo.

“We don’t know how many active police officers are on it,” Davis said of Thee Rant. “If we did identify active officers speaking on the site in that capacity they would be disciplined for violating policy.”

“Unfortunately,” he added, “it’s one of these things that we don’t have ownership of. We don’t have any control over it. Some say that’s good, others maybe say it’s bad.”

Davis said he did not know of any active effort to determine whether current officers are commenting on the site or who they are. He said the department would investigate any specific allegation that a particular officer was behind objectionable comments.

“It’s, in a sense, unfortunate that a lot of it is done under the banner of freedom of expression now,” Davis said.

Polstein, who joined the department in 1988, told the New York Daily News in 2005 that he’d started the blog as his personal diary. “It was how I felt at the moment,” he told the News. “It is my constitutional right to vent.”

Over the years, the local media has occasionally reported on Thee Rant. In one recent instance, the blog decided to go after a reporter who had done a story about the South Carolina shooting comments. One contributor to the blog found a video of the reporter at a conference, posted it, and then encouraged others to mock the reporter’s looks.

The coverage prompted objections from at least one current or former officer, who suggested Polstein should take a more active role in moderating the blog.

“There hasn’t been a moderator on here in days," the officer wrote. “If Ed had any loyalty to active duty cops, he’d remove the law enforcement angle of the board and let er rip. As it is, anytime a lazy reporter wants to smear the NYPD, all he has to do is come here and read the ravings of some diaper wearing geriatric that fell hard off the Aricept train and say that it was an active NYPD cop saying it.”

The NYPD’s Davis said he hoped the police union might step in to rein in the blog.

“A lot of retired people are still active in the union and it doesn’t do anybody any good to have these remarks out there,” he said. “They really don’t help. But that’s the nature of the social media beast right now.”

Al O’Leary, spokesman for the New York City Patrolmen’s Benevolent Association, declined to comment for this story.