We reported on Detroit’s population problems back in October last year.  Not surprisingly, with the loss of 25% of its population in the last ten years, those problems have not gone away. 
Detroit is a case-in-point of what can happen when population quickly contracts.  Once a bustling, successful city (largely due to the automobile industry) the population exodus has left whole neighbourhoods of empty, valueless houses.  Those seeking to take advantage of the situation search the empty buildings for scrap metal and any other valuables.  One can only imagine the rodents that also search for food and shelter within their empty walls. 
This situation has largely arisen because of accounting and cost problems.  Cities come to rely on taxpayer money and Council rates - and many costs are fixed meaning that they don't decrease as people leave the city and accordingly stop paying rates.  While the population and rate base has collapsed, the city’s fixed costs have remained high meaning that public services have become less and less reliable as the city struggles to pay for them.  According to a state report, the city currently has a budget deficit of about $100 million.  The situation is so dire that apparently half the time the police do not even respond to calls from concerned residents. 
A new state-imposed manager, Kevyn Orr, started just yesterday and his job is to try to turn the crumbling city around.  First on his agenda is public safety.  However, his overall goal is to avoid taking Detroit to the bankruptcy court, which would be the biggest municipal bankruptcy in U.S. history.  To achieve this, he has been given sweeping new powers, including the ability to override unions.  While he is optimistic about the city’s future, his job will not be easy.  Reuters reports:

As he travels a sprawling city larger than Boston, San Francisco and Manhattan combined, he will encounter the realities of Detroit's long downward slide...

The number of the city's uniformed police officers has fallen from 3,070 in 2000 to 2,000 today, according to city figures. This has left the department so understaffed officers cannot get to some crimes, even violent ones...

The number of murders per 100,000 people in Detroit in 2012 was around 10 times the national average, according to U.S. government statistics. Homicides rose 9 percent last year.

Detroit Fire Department records show the city has an average of 30 fires daily, most of them suspected arson. Fire department union president, Dan McNamara, said the culprits usually get away with it because of a shortage of arson investigators.

In one case on March 11, Larry Davis, 62, nervously watched a blaze that fire officials said was intentionally set, as it spread to three houses behind his home because the city did not have enough firefighters to respond quickly.

"It's a joke," Davis said as he watched people scouring the charred houses for scrap metal soon after firefighters left. "It's like we're forgotten out here. You can't get the police to come here. Let’s hope that Orr is successful in Detroit for the sake of those that still live there, and that falling populations elsewhere do not lead to the same situation.