The US government has recovered four species of aliens from crashed UFOs, a former CIA researcher has claimed.

The spread of species beyond their native habitat is a human-made environmental change on a global scale. Among vascular plants, over 16,000 species have now permanently settled in foreign countries.

A former CIA-funded researcher has made an astonishing claim, saying that "at least four" different extraterrestrial species have been discovered in crashed UFO wreckage recovered by the US – though n ...