Astronomers previously had only indirect evidence for the existence of these black holes, as they couldn't be directly perceived because of dust and gas.
The discovery was presented at the Royal Astronomical Society's National Astronomy Meeting in Llandudno, Wales. Scientists suggest there may be millions more ‘monster black holes' in the universe than they previously thought.
"For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view," said lead scientist George Lansbury, from the Centre for Extragalactic Astronomy at the University of Durham.
Supermassive black holes are cosmic "drains" sucking material into a point of infinite density, and they contain between a million and a billion times more mass than a typical stellar black hole. Stellar black holes result from the collapse of massive stars.