Sentence:  On one of his 1921 ventures he was actually come upon by a Detective Sergeant John J. Ryan down on his knees with a tool embedded in a <WSD>labour</WSD> office safe in the Postal Telegraph Building ; the jury wanted better evidence than that and he was acquitted , at a cost of $ 30000 in bribes , it was estimated . 
Meaning of the word marked with <WSD> tags:  a social class comprising those who do manual labor or work for wages