Professor Ort-Meyer is the man responsible for the mayhem and murders in Hitman: Codename 47. Believing that mankind was created imperfect (on the last day of creation, when God was tired), Ort-Meyer took it upon himself some
thirty years previous to use his knowledge of genetics and DNA meshing technology to create the ultimate human being (emotionless, without quirks, and completely loyal). The gene donors of this heinous experiment seem to be among the worst criminals the human gene pool had to offer: Triad leader Lee Hong, drug lord Pablo Ochoa, international terrorist Franz Fuchs and gun runner Boris Jegorov. (Given that they all sign their letters 'blood and muscle', this would imply that Ort-Meyer had also served in the French Foreign Legion alongside his investors). At some point, either during their service in the French Foreign Legion or shortly after, they must have discussed the issue of soldiers, competence and subordination; it would then follow that Ort-Meyer, determined to prove his abilities to the scientific world, brought up the topic of engineering the perfect soldier - an effort that would surely be supported by his wealthy subordinates, who were in need of such soldiers themselves. One such creation was Agent 47 himself who, after completing his training at the facility, was 'allowed' to escape by Ort-Meyer, thus unleashing him upon the world to see if he was indeed the genetically engineered killing machine he was made to be.
The reason for unleashing 47 was most likely that Ort-Meyer's experiment wasn't going according to plan. Ort-Meyer's investors in the project (the gene donors) were fed up with his never-ending series of experiments, having apparently invested great fortunes in the project, and insisted that they needed men now (thus implying that the clones were engineered as the perfect soldiers. The cutscenes at the end of the Hong Kong and Colombian missions support this). It would seem that there was a fallout between Ort-Meyer, who wanted to go on spending other people's money on projects; and the donors, who wanted results and probably planned to seize control of the project and 'split the fruit while they could still savour it'. Indeed, Ort-Meyer had already threatened to unleash 47 upon the irate Pablo when (as implied in the letter) threatened to have his funding pulled out. It may be that Ort-Meyer, feeling the noose tighten around his neck, finally decided that he wasn't going to stand any more nonsense from his so-called partners, and sent 47 out into the world so that he could manipulate his 'perfect' clone into killing them one by one.
However the reasons for Ort-Meyer wanting to eliminate 47 are unclear. However, the subject of 47's insubordination problems while growing up in the facility as well as his 'ungrateful' nature were raised by the professor as he unleashed his new series of clones (48) upon 47's head, as well as his claim that it was time to clean the slate and start over, suggesting that Ort-Meyer had discovered 47 wasn't quite as perfect as he would have liked (the 48 series were apparently more obedient and loyal), and decided he didn't want imperfection running wild in the world - especially one who would come to learn the truth about his own creation, and possibly take some form of revenge on the one who made him. If this is the case, then Professor Ort-Meyer is an even more heartless man than the morally skewed DNA contributers that help made 47.