Graffiti calling for the sacking of Everton manager Roberto Martinez has been daubed on to the back walls of two stands at Goodison Park.
The words "Martinez out" were spray painted on to the back of the Main Stand on Goodison Road during the weekend.
In addition, the back of the Bullens Road Stand -- on the opposite side of the ground -- was defaced with the same phrase, along with the words "not good enough."
A member of the club's staff was seen painting over the insults on Sunday morning.
Everton were eliminated from the Europa League on Thursday, suffering a 5-2 round of 16 second-leg defeat against Dynamo Kiev in Ukraine and losing 6-4 on aggregate.
Martinez, who arrived from Wigan Athletic in 2013, led Everton to fifth place in his first season as manager.
But they had slipped towards relegation danger by winning one out of 12 Premier League games before beating Newcastle 3-0 last weekend.
Everton had 31 points from 29 matches ahead of Sunday's game at relegation-threatened Queens Park Rangers.
Martinez acknowledged ahead of that game that his side were far from safe, saying: "Any team who haven't got 40 points in the final third of the season are fighting for every point. Make no mistake about it.
"It's a massive period of the season for us. Every point is going to be extra significant for the team."