After a historic decline, violence and crime are rising again in Rio de Janeiro.

Just this weekend, a police helicopter involved in anti-gang operations crashed in Rio’s City of God favela, killing four officers. It is not yet clear whether it was an accident or was shot down by drug traffickers.

CCTV America’s Lucrecia Franco reports from Rio.

Last month a shootout between police and criminals in another favela left three people dead near the famous Copacabana beach.

Both incidents happened in neighborhoods that have been part of a massive government pacification program aimed at pushing drug gangs out of nearly 40 favelas or slums. The program, created in 2008, has had some success, but incidents like the Copacabana shooting have eroded support. Its architect, Rio’s security secretary, resigned in October.

Though there was a respite during the Rio Olympics, when 85,000 soldiers and police officers were deployed to protect tourists and athletes, violence has since spiked.

More than 3,600 murders in all have been reported across Rio this year through September, a rise of almost 18 percent from the same period last year, according to official numbers.

Now to make matters worse, Brazil is facing its worst recession in a century, with rising unemployment, and police among the many state workers getting paid late. Violence experts are concerned:

Rio is still significantly safer than it was a decade ago, but experts say the war on crime will be tougher with no end in sight to the financial crisis.