Several people have suggested that this week’s column should have been entitled, “Sh*t on a Shingle.”

I get the joke. It’s the story of a San Francisco woman who discovered that the roof of her building in the Mission was covered in dog poop. She didn’t own a dog, and neither did any of the other residents in the building.

So began a case of whodunit, and eventually the city got involved. That’s where events took a twist that no doubt will have many tongues and tails wagging. Did the city do the right thing? Or is this one of those nutty only-in-San-Francisco controversies? Read the column and you be the judge.

While reporting this story there were several attempts to throw me off the scent. Phones were hung up on me a couple of times – people were incredulous, terse, and annoyed. I was scolded for reporting a story that might make the city look bad. Some at first claimed they’d never heard of the incident, and then later admitted that they had. Frankly, no one wanted his or her name publicly associated with a story about dog poop. I can’t blame them – I’m not exactly thrilled that I will now forever come up in search engine results about this topic.

But this is an issue that truly drives people batty: pet owners who don’t clean up after their dogs. As a practical matter, police can only cite and fine dog owners if they witness the dog crapping firsthand (and really, who wants to stand there watching that?). Otherwise, how do you prove where the poop came from?

To some, the answer is DNA testing.

In Israel, the city of Petah Tikva (a suburb of Tel Aviv) has experimented with a DNA database of local dogs so they can be matched to wayward waste – and the pets’ owners punished. Sound crazy? Some cities in Europe are considering the same idea, and here in the United States there have been individual cases where angry neighbors have used DNA from dog poop to go after offenders.

Those smart Freakonomics guys dissected this idea a few years ago in an essay in The New York Times, and even though they wanted to dismissed it as lunacy, they decided there were some merits.

Let’s fact it, America has been obsessed with those CSI television forensic shows for more than a decade – of course we’re going to believe that science is the answer. Even when it comes to dog poop.

I did not have to use such advanced crime fighting techniques to track down the facts for today’s column. It was done with phone calls and letters, and later the details were all sorted out with the dog’s owner over a cup of coffee at the city’s famed Tartine Bakery.

That’s much more pleasant than scraping crap into a test tube.