In the latter part of the ’80s, between fairy tale knights and space janitors, Sierra On-Line and Roberta Williams helmed back to the inspiration that spawned her and the company’s first game Mystery House in 1980, a title that not only became the first adventure to feature graphics but also the seed for ’80s powerhouse and adventure company par excellence, Sierra On-Line. Mystery House was inspired by Agatha Christie‘s 1939 novel And Then There Were None, one of the best-selling books of all time. While 1980 didn’t leave much room for an elaborate character-driven murder mystery game, the late eighties did. Williams started writing on Mystery House’s spiritual successor, The Colonel’s Bequest, after having completed King’s Quest IV in 1988, the same year as Mystery House went into the public domain. The new game was essentially based upon the same premises as Mystery House, and every other murder mystery novel, with murders, detective work, clues, and suspicious characters. The old Victorian mansion was swapped for a Louisiana Bayou plantation in the roaring ’20s where Protagonist Laura Bow is invited by her friend Lillian to spend the weekend for a family reunion.

The company’s many adventure games and especially Williams’ King’s Quest series had heralded not only the adventure game genre for almost a decade but also the company’s internal development tools. Colonel’s Bequest utilized the first iteration of the Sierra Creative Interpreter (SCI0), used first in King’s Quest IV, allowing for high-resolution 16-color EGA graphics, mouse, and soundcard support. The Colonel’s Bequest, when released in late 1989, received positive reviews but seasoned adventure players found the lack of puzzles and overall difficulty disappointing.

Roberta Williams’ The Colonel’s Bequest was released in November of 1989 for the IBM/PC. The following year saw releases for the Commodore Amiga and Atari ST.
Sierra managed to keep the Quest name in the title, Bequest meaning the act of giving or leaving something by will 

The 16-color high-res EGA graphics looked absolutely wonderful, depicting the Art Deco style, and are probably some of the best graphics created for an EGA game.
The beautiful and atmospheric graphics alongside the fitting music, interesting story, and many characters made The Colonel’s Bequest a charming and intriguing game.
The game is divided into eight acts, one for each hour, with each hour broken down into fifteen-minute quarters. The clock advances 15 minutes when certain triggers are met, typically when walking into certain rooms or interacting with certain people, an interesting approach giving life to the story you’re journeying through but makes it way too easy to miss important events

Sierra followed up on The Colonel’s Bequest in 1992 with The Dagger of Amon Ra: A Laura Bow Mystery, a game that wasn’t written by Williams, who was hard at work on King’s Quest VI but by writer and designer Bruce Balfour. Balfour had earlier worked with Interplay which published his first game Neuromancer in 1988. He joined Sierra as the producer, director, and designer on The Dagger of Amon Ra.
Williams acted as a creative consultant and was involved in the initial development phase before Balfour took over and completed the story with writing assistance from Josh Mandel.
The story takes place after Laura Bow has graduated from college and moves to New York City where she lands a job at a major newspaper. She’s given a small and unimportant assignment to cover the opening of the new Egyptian exhibit at one of the city’s museums, the location where the majority of the game and all of the rather gruesome murders takes place.

A follow-up to The Colonel’s Bequest came in 1992 with the title The Dagger of Amon Ra: A Laura Bow Mystery.
Roberta Williams was one of the most recognized game developers of the time and marketing made sure her name was represented on the box even tho she wasn’t much involved in the development.
The text parser was swapped for a point-and-click interface and the graphics were in 256-color VGA

The 1993 multimedia version featured full voice acting and narration.
To keep the cost down several Sierra employees including Jane Jensen, Scott Murphy, Bruce Balfour, Josh Mandel, lead programmer Brian K. Hughes, and Lorelei Shannon, were all used for the voice acting