The case of an Oxford University astrophysicist who was found dead in mysterious circumstances took a dramatic twist on Friday when his wife said she believed the death was an accident and not murder as initially suspected.

The body of Professor Steven Rawlings, 50, was found on Wednesday night at the home of his close friend and fellow Oxford academic Dr Devinder Sivia, 49, after a neighbour called police to report an incident.

Sivia was arrested on suspicion of murder that night and released on bail on Friday morning until April 18. Police said an autopsy conducted on Rawlings' body was inconclusive and further examinations were needed.

Later on Friday, Rawlings' wife Linda said she did not believe her husband had been murdered.

Steve and Devinder were best friends since college and I believe this is a tragic accident, Linda Rawlings said in a statement emailed to journalists by the police on her behalf.

I do not believe Devinder should be tarnished in this way, she said.

Police made no comment on her statement.

Rawlings' sudden death has shocked the 900-year-old university, where he held a prestigious post as professor of physics and had led the astrophysics department from 2006 to 2010.

The entire university community has been profoundly saddened and shocked by the tragic and untimely death of Professor Steve Rawlings, said Oxford's Vice-Chancellor Andrew Hamilton, the university's senior officer.

Sivia is a lecturer in mathematics for the sciences at Saint John's, one of the 38 colleges that make up the university.

The college is shocked and distressed by this tragic event, said Sir Michael Scholar, president of Saint John's.

Rawlings, who lectured on vector calculus to first-year undergraduates, was based at another Oxford college, Saint Peter's.

He was a much-liked and admired tutor and colleague within the college and will be greatly missed, said Mark Damazer, master of Saint Peter's, in a statement.

Rawlings was one of the lead scientists in the Square Kilometre Array (SKA), an international project to create the world's largest radio telescope.

The SKA will give astronomers insight into the formation and evolution of the first stars and galaxies after the Big Bang, the role of cosmic magnetism, the nature of gravity, and possibly even life beyond Earth, says the project's website.

Sivia teaches maths for natural sciences to physics and chemistry undergraduates.

My research interests revolve around the application of Bayesian probability theory to all sorts of data analysis problems, mainly in the physical sciences, he says on the Saint John's College website.

(Reporting by Estelle Shirbon, editing by Paul Casciato)