They had performed in Phoenix, Arizona and were driving to a show in Santa Ana, California. Authorities in Arizona say a pickup truck and a van collided head-on about 75 miles (120 kms) west of Phoenix, killing the truck's driver and three people in the van. Officials did not name the victims.
The Liverpool-based duo released its debut album, "Invitation to Her's," last year. The record company said in a statement: "We are all heartbroken. Their energy, vibrancy and talent came to define our label."