Amy Winehouse's husband Blake Fielder-Civil and three others were being investigated for alleged trial fixing. The singer is not said to be involved. The husband of British singer Amy Winehouse has been arrested in an investigation into perverting the course of justice, days before he is due to go on trial accused of beating up a bartender. Pictures in Friday's (November 9) Daily Mirror newspaper showed Winehouse, 24, kissing husband Blake Fielder-Civil, 25, before he was led off in handcuffs by plainclothes police during an overnight raid at an apartment in East London. A police spokesman said: "We arrested four men -- two 25 years old, one 22 and one 19, in connection with an allegation of perverting the course of justice. Currently they are in custody at North London police stations." Fielder-Civil goes on trial on Monday (November 12) on charges of inflicting grievous bodily harm with intent, over allegations he and another man beat up bartender James King. The Mirror said it had tipped off police after it received evidence there may have been an attempt to pay witnesses to change their stories. An accusation of perverting the course of justice, like the grievous bodily harm charge itself, could carry a potential life sentence. A spokesman for Winehouse said the singer had no comment over the arrest. Earlier on Thursday (November 8) evening, police crashed into her house in North London with crowbars, but neither she nor Fielder-Civil were there. Winehouse, who scored a hit last year with the song "Rehab" about refusing drug and alcohol treatment, has been dogged by allegations of substance abuse, no-shows at concerts and erratic behaviour. She, Fielder-Civil and a friend were arrested last month in Norway for possessing cannabis and paid a fine.