The Hidden Blade Assassin's Creed in Depth

Just run around the city until you find one. I have found a couple but I think that you have to let them tackle you so that you can get your money back. First time I killed one and it didn't show, second time I just tackled him and nothing.

I'm beginning to think you might need to have 1 or more Assassin Dens in Templar control. I haven't found any other way to flush them out. I even patiently walk around calmly with full Templar awareness.

I don't know anymore, I have all dens guarded by Master Assassins but they still show up once in a while. The last one appeared near Galata Mosque but he fell off a roof during the chase :/

We need our experts to find some exploit or a place where they show up more often than others. That or Ubi needs to update it so they come out of the shadows more often. :/

I've been doing some "research"
It seems that they show up mostly after a bank deposit has been made. As for the location, the shops near Hagia Sophia's tunnel entrance is the most recurrent one.
Here is the best info I could find: http://www.trueachievements.com/achievement.aspx?achievementid=157173

Or if you don't want to check the page

EDIT: Just checked it and it seems like it works, although I haven't double checked. I was wondering why I didn't get the achievement and they I realized I got it a few days ago without realizing

That works, but make sure to go to the Hagia Eirene, look at the map, and withdraw from the bank south of it. Within 5 seconds, I saw him on my map and took him out with the hook sweep before he knew I was there.

I got the achievement without the guy taking any money. I saw the logo on the map and I thought it was a pickpocket so I chased him and he climbed to a rooftop. I killed him with throwing knives, looted him, and got the achievement. It was only when I looted him that I noticed he was the tax guy xD

It's really funny that even in games tax is still a hot issue and tax problems are present but it's fine by the way since it's just in computer games but when it comes to real life, tax evasion and tax fraud is a big no.
At present, tax fraud is on the rise and in fact, there are now tax-cheating programs and it's very alarming for the government. Because of this, States cracking down on tax zapper programs keeps on increasing. More states are now passing or considering regulations to ban so-called tax zapper programs. The software programs, that a few say cost the states billions a year in tax revenue, create a second set of books when a thumb drive is placed to the cash register. The second set of numbers used for tax reasons, under-reports the salary of the business. Many states are starting to crack down on businesses that use so-called "tax zapper" programs to keep two sets of books by simply inserting a thumb drive into the cash register. States say the programs costs them billions in unreported taxes. A personal loan can help you pay your taxes.

SWAT!