Sunning herself at Piscinao de Ramos, a man-made saltwater lagoon in Rio de Janeiro's North Zone, Adriana de Araujo Silva, 28, looked along the sandy beach.
"I'd much rather be here than at Copacabana," she said, referring to the pool area created in 2001 as an alternative to the polluted natural beach on Guanabara Bay, a few yards away.
Rio de Janeiro's beaches are often celebrated as democratic public spaces, bucking the trend in Brazil for minimal social contact among the classes. But for some cariocas, as Rio residents are called, the idea of harmony at the beach is little more than a myth.
At Copacabana, when other beachgoers hear the way she and her children speak, Silva said, they "look down on us."
"They can tell we're from the favela." Silva nodded, referring to one of Rio's hundreds of slum areas. Consequently, she said, fellow beachgoers look at her boy and girl, both around 10 years old, "as if they were going to steal something."
Silva is a resident of Pinheiro, which, along with Ramos, home to the popular lagoon, is one of 16 favelas making up Complexo da Mare, a sprawling community of 140,000 people. Currently the subject of a citywide drive to establish a police presence in favelas, Mare contains some of the city's most troubled neighborhoods, as well as more peaceful communities like Ramos.
A hundred yards down the beach, Leila Mara, 41, had set up camp on the sand with her husband, Michel, her teenage daughter, Ana, and Ana's boyfriend. A pair of coolers under a beach umbrella were packed with lunch, drinks and snacks. "We have everything we need for the day," she said.
For Mara, another resident of Complexo da Mare, Copacabana also spells trouble, but for different reasons.
"Here in the community there's a code of behavior," she said. "Nobody messes with anyone else."
At Rio's internationally known beaches, she said, it's a different story. "You hear about terrible things going on down there: theft, arrastoes, all kinds of confusion."
Mara was referring to mass robberies that occasionally take place on the beaches of the affluent South Zone neighborhoods of Copacabana, Ipanema and Leblon. The word "arrastao" translates as a "dragnet," reflecting the way the groups of thieves, usually youths, spread out as they dart along the beach, stealing wallets and phones from those in their path. Arrastoes have taken place occasionally for more than two decades, with the latest wave, over a weekend in late September, causing panic among beachgoers.
The outbreak ended as quickly as it had begun, but ripples of indignation reached far beyond Rio, once amplified on social media and in news reports.
At South Zone beaches, many blame robberies on youngsters from communities like Complexo da Mare. "They come down here with no money," said Antonio Eugenio de Rocha, 61, who sets up and collects deck chairs on Ipanema beach. "They jump the bus to get here, then steal what they can to get home again. It's never the kids from local favelas," he said, nodding toward Vidigal, high on the mountainside overlooking Ipanema.
Rio's status as a dream vacation destination, as well as its role as host city for the 2016 Olympic Games, make security on the beaches a matter of paramount concern to city officials.
Taking no chances, Rio de Janeiro state Security Secretary Jose Mariano Beltrame reacted forcefully to the September arrastoes, deploying 734 officers along the 4.8-mile shore between Leme and Leblon the following weekend, supplemented by 380 municipal guards and 60 social workers.
As Saturday dawned, a police helicopter buzzed along the shoreline, sending live video to a control room; meanwhile, a pair of armored cars patrolled the long promenades like miniature tanks.
Enjoying a stroll close to Arpoador, a rocky outcrop separating Copacabana and Ipanema beaches, U.S. tourists Vivian and Nathaniel Smith of New York's Long Island were on the first leg of a 22-day tour that would also take in Argentina, Chile and Peru. Though she had been warned about petty crime in Rio, Smith, 70, said she was surprised to hear of the mass robberies. "It explains why our tour manager told us to avoid wearing any jewelry," she said. But noting the substantial police presence, she said, "We feel safe here."
More controversially, police operations that weekend included roadblocks, in which buses from the North Zone were stopped and searched in an attempt, critics say, to discourage the flow of youngsters from poor neighborhoods.
North-south bus lines were halted at 17 roadblocks that weekend, and more than 50 unaccompanied children were removed from the buses and transferred to social centers to await their parents or to be referred to municipal child-care institutions.
Beltrame called the operation a legitimate intervention in the lives of "socially vulnerable minors." But critics say youths have the right to travel freely.
"The problem starts when fear is manipulated to reinforce the idea that certain parts of the city should not be frequented by certain people," said Atila Roque, executive director of Amnesty International Brazil.
The fear of being robbed or of suffering violence, he said, is legitimate: "Everybody has the right to feel afraid.
"But everyone also has the right to go to the beach," Roque said.
"Just because a person has no shoes on, or no shirt or no money in their pocket, that doesn't mean they should be classified as someone about to commit a crime."
Those singled out for suspicion, he said, are young, poor and predominantly black, and yet they are in significantly more danger of violence than any South Zone resident, Roque said. That includes violence by police, he said, citing four children ages 10 to 13 who were fatally shot during police operations on the streets of Rio favelas in 2015.
In November, in the North Zone neighborhood of Costa Barros, five young men returning home from a day out were shot by four police officers, who sprayed the car they were riding in with more than 100 bullets, according to a police report. In a scene witnessed by one of the victims' brothers, age 16, riding his motorbike home alongside the car, all five friends, ages 16 to 25, were killed.
"The fact of a child being killed in Complexo da Mare, Complexo do Alemao or any other part of the Baixada Fluminense" — the densely populated region just north of Rio's city limits — "is simply accepted by society," Roque said. "It's seen as barbaric, but it is accepted."
Only especially shocking cases, or deaths that are filmed, arouse society's indignation, he said. "Yet when the slightest trouble breaks out in Ipanema, Leblon or Jardim Botanico, the problem is elevated to a national crisis."
Rigby is a special correspondent.