Have you experienced any in your career?
Something you try hard to avoid since it normally results in you getting fired. I have seen a fair amount of AP fraud. The only PR fraud I have seen was a long time ago at a manufacturing facility where we gave the checks to the supervisor to hand out (bad idea). The supervisor would not tell anyone when an employee left, kept their time card filed in and cashed the checks. Fortunately I had told management that this method was a bad idea (in writing) and they over-ruled me, Since we had 1,000+ hourly employees, it was very easy to miss a termination if the supervisor is playing games.
Checks are a bad idea. Doing anything but US mailing the check is a very bad idea. Checks are the fraudsters best friend.
I've seen 2 actual and a few clumsy attempts.
The first was when I first started in payroll and an admin for our sales department would submit a list of route/delivery payments to payroll weekly, with no one signing off on it. She would cash the checks for some of these employees and they would split the money. A few people got fired for that one as it went back for several years.
The second one was through AP Someone submitted several fake checks that they printed at home. The largest was for around 50K. This was before heat changing signature line, watermarks and positive pay.
Not the question, but I generally had both PR and AP report to me, and most fraud is on the AP side (in my experience). I had a manager who paid a "consultant" $5K a month on his expense report. Turned out the "consultant" was also his GF. This had been happening for years, and it violates maybe a half dozen normal process rules. Several people not related to the fraud were not doing their job.
Fraud is a function of process. Set up a good process and you make fraud very difficult. Even if you have fake invoices, there should be approvals and POs. Maybe even detailed budget references. Do you have a second person review all invoices? Do you send a monthly report to supervisors detailing their expenses for the month? Do you periodically rotate which vendors the AP clerks handle? Do you have mandatory two week vacations for AP/PR staff? Many frauds require active management. Do you have mandatory POs over a certain amount. It is much harder to manage a fraud when more people get involved. Also, staff if never 100% honest or 100% dishonest. They are occasionally weak. Good process discourage staff from doing something stupid. You can never stop all fraud, but you can make it very difficult.
Lastly, teach your staff everything you know about everything. Especially fraud. Get as many eyes out there as possible. Pay bonuses for finding and closing holes. Praise is fine and use it when earned, but an unexpected $100 bonus can make an AP clerk move mountains.