In 1961, Sowman was on duty at headquarters when Frank Barlow phoned the station to report his wife Ida missing. When Frank's description of Ida matched that of a woman who was knocked down earlier that day, Sowman sent a Constable to Coronation Street to tell Frank that his wife was dead.
The following year, Sowman was summoned to Elliston's Raincoat Factory in the same street when machinist Christine Hardman was contemplating jumping off the roof of the factory. He failed to talk Christine down but luckily Ken Barlow convinced her.
Later that year, Sowman, now a plainclothes detective, was called to Coronation Street when baby Christopher Hewitt went missing. Sowman questioned various witnesses but Christopher and his pram were returned by Joan Akers, who had taken the baby from outside Gamma Garments.
In 1965, Sowman tried to track down a woman who had fled the scene of a car accident when driver Robert Maxwell had had a heart attack and died while driving. Sowman discovered the identity of the woman was Elsie Tanner.
- Sowman first appeared in Episode 78 and was credited as Headquarters Sergeant. On his next appearance in Episode 156 he received the credit of Policeman (but also gave his first name of Harry during a telephone conversation). In Episode 189 he gave his name and was credited as Det Sergeant Sowman in all subsequent appearances.