About 66 million years ago, the disappearance of the dinosaurs is like the ultimate "Cold Case" where there are no eyewitnesses, partial physical evidence that is ancient and some researchers who are still hopeful of solving the mystery.

A team of international paleontologists now thinks that they have a suspect which could be a comet or an asteroid that made the dinosaurs suddenly disappear. But the researchers also said that whatever impacted the Earth which led to disappearance of the dinosaurs also had accomplices like the changing levels of sea, changing climate and also a number of eruptions that changed the geological constitution of whole of the Earth.

"It's bit of a more nuanced story that's coming together", says Stephen Brusatte who is a paleontologist at the University of Edinburgh in Scotland as well as the lead author of a study that is making the case in the journal Biological Reviews.

The first fossil record of dinosaurs appears between 245 and 230 million years ago. The birds of the present time are widely thought to be descended directly from the small theropod dinosaurs.

The team of researchers also noted that the dinosaurs disappeared as a part of a larger mass extinction that made about 75% of all species vanish from the face of the Earth. Some small pockets of dinosaurs were there on the Earth for a while but they also ultimately gave way to other species.

The team of researchers also suggests that environmental changes induced by volcanic eruptions may also have affected the communities of dinosaurs in some ways during that time, like the changes in community ecology or the structure of the population or at some regional levels that may be undetectable in the present fossil record that the researchers possess.