Guido Schuette, 48, is believed to have died in explosion but officers say if anyone does see him alive they should call 999

Police have warned the public not to approach a man missing since an explosion destroyed a block of flats in Oxford, despite saying they “strongly believe” he died in the blast.

Guido Schuette, 48, is the last person unaccounted for since the explosion and fire on Valentine’s Day levelled the block on Osney Lane. Members of the public have been urged to call 999 if they see him.

Speaking at the scene on Thursday, Supt Joe Kidman said: “Our strong hypothesis is that Guido died in the fire, and we are continuing to offer support to his family at this time. However, while our search of the scene continues and this is not confirmed, one line of inquiry within the investigation is that Guido could be missing. Given the circumstances of the incident, we are asking members of the public not to approach Guido but to call 999 immediately.”

Schuette, who is believed to walk with a limp and use a crutch, was described as 6ft tall, of heavy build, with short grey hair and blue eyes.

Emergency services were called to the Osney Lane and Gibbs Crescent area at 4.45pm on Tuesday after a blast ripped through the three-storey building. Police and fire chiefs said they were investigating but no cause has yet been given for the explosion.

Facebook Twitter Pinterest Work is ongoing to make the blast site safe before a search can take place. Photograph: Geoffrey Swaine/Rex/Shutterstock

Two people were treated for minor injuries following the blast, one of whom was transferred to the John Radcliffe hospital, and residents were evacuated from 40 homes, 19 of which remain empty due to continuing danger from the damaged infrastructure.

“Oxfordshire county council fire andrescue are undertaking significant work to make the site fully safe,” Thames Valley police said. “Until this work is done, crime scene investigators, fire investigators and dog search units cannot access the site in order to confirm that [Schuette] is deceased.”

The council’s incident commander, Julian Green, said: “Clearly the sequence of events has to be to make the buildings safe first before the removal of rubble begins, so as to ensure safety of personnel. We are expecting to start removing rubble later today, working with fire and police investigators alongside to determine the cause of the explosion.”

Ben Brewis, who was working in the nearby Thames Business Advice Centre at the time, told the BBC: “I still can’t get my head around the force of the blast. The ground shook and the lights dimmed even though we’re a few streets away over the river. We thought a lorry had ploughed into the building or a plane had crashed nearby. The whole of Oxford heard it. It was no rumble, but a huge blast.”