Pensioner's disappearance joins list of unsolved cases

On Tuesday, relatives of the 81-year-old held an emotionally-charged press conference appealing for help to find him on the first anniversary of his disappearance.

After initial extensive police searches involving specialist dog teams, divers and the Humberside Police helicopter, missing persons officers have scaled down the inquiry to "inactive" status and are waiting for fresh leads to follow up.

They have investigated 35 reported sightings of the retired council gardener in Bridlington, where he has a twin sister, and in Hull, Leeds, York, Leicester, London and Boston, none of which was fruitful.

They also showed his family footage of last year's Remembrance Day Parade in London after reports that he was spotted in the crowd, but the person identified was not him.

This is just one case in a daunting workload for the small team in Hull, which handles – on average – 100 reports of people going missing in the city each month.

Although some can be easily explained and resolved, such as teenagers deciding to stay with friends, others – such as Mr Conboy's – are accompanied by the ongoing anguish of families desperate for answers.

Mr Conboy's nephew Paul Robinson, 47, said it was "heartbreaking" for his family, which was enduring "the daily torture of not knowing".

In the last 12 days, 12 people have been reported missing in Hull, in cases classed as "active".

Mr Conboy, of Saxcourt, last spoke to his sister Ellen King in a telephone call at 10.30pm on Sunday April 19 last year and has not been seen or heard of since.

When his Mrs King called him the next morning there was no answer and his bungalow was empty when she went round. The curtains were drawn and the lights were on, suggesting he may have left the previous night or in the early hours.

His family believe that Mr Conboy was confused after being treated for a viral infection at Castle Hill Hospital in Cottingham, three weeks before he went missing.

Anyone with information can call 0845 606 0222.