He is described as a big policeman when he accuses John of interfering with the houseboat. He curtails this investigation because he is afraid of Nancy, who threatens to tell his mother Mrs Lewthwaite that he is unfairly accusing her friend.(SA24)
When the Lake freezes over in winter, Peggy says when she sees him testing the ice "If it'll bear him it'll bear anyone" (WH7). Later (WH29) he is called out to look for the missing explorers of the North Polar Expedition.
When The Ds burgle Captain Flint's study at Beckfoot, (PM20,21) he investigates the burglary, but, partly due to Nancy's success in misleading him, he draws the wrong conclusions and later the Great Aunt regrets that she cannot have a word with the police sergeant or his mother (PM29).
Nancy says Sammy "...isn't afraid of anyone except his mother...and us of course."(SA24) He is quite good for a policeman He asked her if she could be sure of the colours (of the burglar's clothes) in the moonlight and she had to explain that she had only seen the colours in the daylight when you (Timothy) were loitering .... and first rate again, she says Old Sammy was grand when he asked the G.A. for details of the missing items when he is investigating the Beckfoot burglary (PM21).
Sammy's younger brother Billy lives with his mother, but it is uncertain whether Sammy does also; they both appear to be single. After the burglary the GA rang up the police in the middle of the night, but there was no one they could send, which suggests that Sammy was not living in a police house with a telephone (PM21).