The couple were described as "prominent and much-loved" figures in their community.
Mr Johnson, elected as council leader earlier this year, had helped organise the town's Christmas market, launched at the weekend as part of a series of festive events.
On Friday he attended the opening of a Waitrose store in nearby North Walsham along with other signatories.
Mr Johnson's close friend, Benji Cabbell-Manners, had been away for the weekend and told the Eastern Daily Press of his "terrible shock" at hearing the news.
More top news
A big difference in temperatures again today
An inquest into the 2015 terror attack has heard tour operators wanted to increase security but did not want holidaymakers to be "scared".
Jay Oxley was diagnosed with a rare form of cancer and had to be put into a coma.