A £250,000 reward has been offered to track down the killers of a much-loved goose that was killed in an alleged drive-by shooting in a Hertfordshire village.

Grumpy Gertie had been a fixture on a pond in Sandon, just east of Letchworth Garden City, for the past 11 years. It had even been pictured on a sign in the sleepy village that is home to about 200 people.

The goose was reportedly killed on the Rushden Road pond last Sunday by a man who leaned out of a 4x4 vehicle and opened fire.

The incident has so outraged one person that he has offered the substantial reward to bring those responsible to justice. Peter Hunt of Eastbourne texted the Jeremy Vine show on BBC Radio 2 on Friday to offer the reward, although no further details appear to be available. The Guardian can confirm that the reward was not posted by the Peter Hunt who runs a driving school in the East Sussex seaside town.

Jean Handley, who lives in Sandon, told Vine that villagers were incensed by Grumpy Gertie’s death. “He’s been around for years. Everyone is really upset about it,” she said. Flowers and tributes to the goose have been left in a disused phone box in the village that Gertie used as “his little house”, according to Handley. Its body has been buried near the pond.

A spokesman for Hertfordshire police said the force was investigating the incident with the RSPCA. “It is a reckless and senseless act to shoot a goose in the head at point-blank range,” RSPCA inspector Stephen Reeves told the BBC.