I saw it in a episode of a documentary series called Dark Science I believe it was called?
The higher ups were disgusted by the idea of it, and it only occurred once the first time and subsequent first failure, after that officially it never happened again, because they saw it as immoral, but the head scientist who believed in the hybrid, this was his dream to create a human hybrid was said to have done it himself for the sake of the project off the record, according to surviving accounts of those who worked on the project.)
It may be heresay but that's all that was available once the project was revealed to the public well after the fact because the government records were very sparse.