Murder at the Gasworks (en Inglés) - Lisa M. Lane

A gasworker murdered. A boy accused. A detective out of his depth.

London, 1860. Ten-year-old workhouse escapee Tommy Jones is accused of murdering his only friend, a stoker at the gasworks. When the assigned City Police Inspector falls ill, shy, intellectual Sergeant Cuthbert Slaughter is put on the case. 

As a second gasworks murder across the Thames is revealed, Slaughter must secretly collaborate with a rival detective to prevent a horrible injustice. Are the two deaths connected? If Tommy was not the killer, who wanted two stokers dead?

A mysterious cloaked man spying on the Bank of England, a poor clerk whose wife is under arrest for pilfering, the dumping of noxious substances into the river, all seem to be related. Hampered by his reticence, Slaughter must use all his wits to save the boy.