According to the Liverpool Echo, the forward was taken into custody in the early hours of Friday morning after police were called to a property.
The local source report that the 26-year-old was later bailed, although there will be further enquiries into the incident.
As reported by the Echo, an official from Everton has acknowledged that there is investigation underway, but stopped short of criticising Niasse.
“The club condemns unreservedly any form of abuse,” the spokesman began. “In this case, we understand an investigation is underway to establish the facts.”
The incident completes a miserable six months for Niasse since moving to England from Lokomotiv Moscow on transfer deadline day.
EXCLUSIVE: Arsenal plotting to poach Chelsea’s Nigerian wonderkid Fikayo Tomori
Man City coach Pep Guardiola compares Barcelona life to Bundesliga experience
Video: Zlatan Ibrahimovic transfer – Manchester United target confirms he knows his next move
The forward moved to the club on a £13.5 million deal [fee as per Sky Sports], but has struggled to make an impact, having played just 29 minutes since completing the move.
The 2015 Russian Premier League player of the year boasts immense physical capacities—notably searing pace—but has had to contend with injury and has failed to contribute significantly as Everton have endured a significant slump in form.