Cologne have confirmed coach Frank Schaefer has resigned with immediate effect.
Schaefer, who took over from Zvonimir Soldo in October, had already announced he would be leaving his post at the end of the season. Sporting director Volker Finke will take charge of the team for the remaining three matches of the campaign.
Cologne lost 4-1 at relegation rivals Wolfsburg on Sunday to slip to within three points of the bottom three. Supporters made death threats against his team in the wake of the loss, a group of fans leaving a banner at the club's training ground on Monday which read: "If you go down we'll kill you.''
Cologne have lost their last three games, including a 5-1 defeat to fellow strugglers Borussia Monchengladbach, and have conceded 18 goals in their last five games.
"I take the responsibility in my position to make the best decisions for the club and the team,'' Schaefer said on the club's official website.
"In view of recent results and in particular of the way we've played I have come to the decision that for the remaining games the team urgently needs another change and above all new impetus.
"I have come to the realisation that at the moment I can no longer help the team in the way I consider necessary and therefore have decided to take this step.''
Schaefer insisted his relationship with Finke was not a factor in his departure.
He added: "I would like to make it clear again that the tensions reported in the media between Volker Finke and I have not been a factor in my decision. On the contrary, I am glad that Volker Finke is taking over the team for the short term in this difficult period. My greatest wish remains that we all achieve our big goal - survival.''
Finke, who said he had no interest staying on as coach beyond the end of the season, admitted he was taken aback by Schaefer's resignation.
"The decision by Frank Schaefer has surprised me as we search for a new coach for next season,'' he said. "I regret his decision very much. The board and the management have together asked me to take over the team immediately for the short term. I have always said I would not return to the dugout, but in this exceptional situation it's about mustering all the strength we can.''
Cologne president Wolfgang Overath revealed the board had tried to persuade Schaefer not to resign at such short notice, but without success.