The former Arsenal star, who is currently on loan at Sevilla from Manchester City, was caught up in a Twitter hacking incident on Wednesday after he was named in a tweet by an account called @DripDoctors which claimed he had been given an immunity IV drip.
What followed was a series of bizarre tweets from Nasri's own account claiming the France midfielder had slept with the woman who administered the treatment (you can see them below).
Nasri later said his account had been hacked, but things have now taken another turn for the player.
https://twitter.com/SamNasri19/status/813957171817824256
It has now emerged that he is being investigated by the Spanish Anti-Doping Agency (AEPSAD) over the drip he is said to have received in LA, in case it broke World Anti Doping Agency (WADA) rules.
AEPSAD said it had "commenced an investigation into treatment used by football player Samir Nasri".
The statement added: "AEPSAD wants to gather all the information and check what happened. We must be very prudent at the moment. We can't prejudge the player."
According to the Drip Doctors website the immunity IV drip is one litre of hydration designed to "combat superbugs and common viruses".
The WADA limit for active athletes is 50ml, unless "received in the course of hospital admissions, surgical procedures or clinical investigations".
Here are the tweets in full...
These were deleted, as was the following tweet, which appears to be the final one sent.
These were deleted, as was the following tweet, which appears to be the final one sent.
