Astronomers behind the most extensive search yet for alien life are investigating an intriguing radio wave emission that appears to have come from the direction of Proxima Centauri, the nearest star to the sun.

The narrow beam of radio waves was picked up during 30 hours of observations by the Parkes telescope in Australia in April and May last year, the Guardian understands. Analysis of the beam has been under way for some time and scientists have yet to identify a terrestrial culprit such as ground-based equipment or a passing satellite.