The 19th century was a period in which matters of law and order became steadily more regulated, not least through the professional incorporation of local police forces throughout Britain. Incarceration and sentencing became less of an arbitrary practice as a result, with less opportunity for the well off or well-connected to buy themselves out of trouble.
The case detailed in this broadside is an unusual one because the perpetrator has committed a capital crime (murder) but has nonetheless been sentenced to penal transportation, rather than death by hanging or incarceration for life in a British prison. Transportation was the name given to the practice of sending criminals to penal outposts in colonial territories, particularly Australia. While the practice had been ongoing since the 17th century, by the time of this case transportation was widely used as a means of meeting labour shortages in British colonies. It was therefore usually reserved for very minor crimes (pickpocketing, theft), which meant it was mostly used on the very poor.
Transportation had one advantage over traditional incarceration in that long-serving prisoners could apply to colonial governors for various otherwise proscribed freedoms, which meant that some were able to marry and start families even while technically still prisoners.