1 Caption: Six weeks later:
1 Shakespeare: The screenplay for the pilot episode of our show is done!
2 Shakespeare: Our hero travels to 1536, to research the reign of Henry VIII and the childhood of Queen Elizabeth.
3 Shakespeare: There, his aunt witnesses Robert Pakington, MP, become the first person to be murdered by a handgun in London.
4 Mercutio: Ooh! What if she did it! What a twist!
4 Ophelia: In episode one?
4 Mercutio: We want to beat Game of Thrones.

Robert Pakington was indeed a real person.

The joke here was inspired by my favourite fan theory about Murder, She Wrote. Namely, that Jessica Fletcher is not the murder-mystery-solving sleuth/novelist that she claims to be, but rather that she is a serial killer who covers up her crimes by framing anyone and everyone around her, before moving on unfettered to her next victim.

As TV Tropes points out:

... there is no better explanation for the sheer number of murders the lead character encounters throughout the long run of the series than her involvement in all of them. Indeed, if Cabot Cove alone were really to have suffered that many murders, it would top the FBI national crime statistics by several orders of magnitude. Not only does it see more homicides in a season than the entire state of Maine sees all year in real life, but the town has an estimated murder rate eighty-six times that of the most murderous city in the real world, Caracas, Venezuela. Also, if you're Jessica Fletcher's friend in any capacity but not an episode regular, you're pretty much doomed either to kill someone* or be killed, or be wrongly arrested for being a killer.

* Or be framed by Jessica for killing someone who she herself has killed and dismembered into multiple barrels of acid.