Robert Del Naja, a member of the group Massive Attack, has denied accusations of viewing child pornography, and has been released on police bail. BBC News Online looks at the group and how it topped the charts.
Massive Attack began life as a trio [3D pictured far left]
Massive Attack were one of the pioneering groups producing the "trip-hop" sound of the 90s.
The trio emerged from the Bristol music scene which also produced the likes of Portishead and Tricky.
They began as a loose musical collective under the name the Wild Bunch, that also included influential producer Nellee Hooper, best known for his work with Soul II Soul.
When the Wild Bunch folded, three of its members - Andrew "Mushroom" Vowles, Daddy G Marshall and Robert Del Naja, aka 3D - teamed up to form Massive Attack.
Their first album in 1991, Blue Lines, was critically hailed, and featured singles which have stood the test of time.
Robert Del Naja has stuck with Massive Attack
One of the band's biggest hits was the orchestral Unfinished Sympathy which featured the vocals of soul diva Shara Nelson.
She also appeared on the classic tracks Safe From Harm and Daydreaming but she departed to work on solo material.
By 1994 their follow-up album Protection was released, and again it was highly praised and also became a commercial success.
The album featured the vocals of Tricky, who was making waves as a solo artist, and Everything But the Girl's Tracey Thorn.
Three singles were released including the haunting title track with Thorne singing.
The trio then spent a great deal of time touring and playing festival dates as well as remixing tracks for other artists including Madonna and Garbage.
Fans had to wait another four years before the appearance of third album Mezzanine.
The biggest single to emerge from it was Teardrop with the Cocteau Twins' Elizabeth Fraser supplying the vocals.
But following a US and UK tour the cracks started to show and Mushroom left the band, leaving 3D and Daddy G to work as a duo.
Daddy G also took time out to concentrate on raising his family, leaving 3D to work largely alone on the band's next project but bringing in producer Neil Davidge to help.
In February 2003, after a five-year lull, Massive Attack returned with their fourth album 100th Window, which entered the UK charts at number one and continued their reputation for breaking new ground.
The group have also been famed for speaking their views on world issues. During the Gulf War they changed their name to just Massive to avoid any implication they approved of an attack on Iraq.
The band's moniker was soon reinstated, but 3D has continued to be an outspoken campaigner against another war in Iraq, joining marches and making speeches opposing any US attack on the country.
As well as being a musician he is also an artist, and he has exhibited his work which includes painting and computer-generated imagery.