According to the police report, the suspects were caught while they were trying their luck with impoverished immigrants in Spain's eastern region of Valencia.
An NGO worker working with migrants in the region was the one who took the matter to local police.
The Lebanese man and his four associates had already covered the cost of several candidates’ medical check-ups to determine their organ compatibility.
Spain has been the world leader in organ transplants for the past 22 years, with 35 out of every million people donating their organs.
A national record was set last February, when 45 organ transplants were performed in a single day.
According to several Spanish media sources, this was the first attempt to carry out an unregulated organ transplant on Spanish soil.