Philipp Henschel reported elephants confirmed in the Mount Assirik area of the park in 2013. There were also a few sightings of one small group (ca 10) in 2012, while he was in the park. He states that there cannot be more than 10-15 elephants present.
Source:Henschel, P. (2015). Personal Communication: Information on Elephants in Niokolo-Koba National Park. E-mail to C. Thouless, 8 December 2015.