Stephen King’s serial thriller “The Green Mile” turns another gruesome corner when the fourth installation becomes available in bookstores today.

“The Bad Death of Eduard Delacroix” picks up Paul Edgecombe’s memoir about death-row inmates at Cold Mountain Penitentiary and the strange happenings that occurred when he was a guard there in the 1930s.

The principal characters are the convicted murderer John Coffey, whose hulking hands have healing powers, wild boy William Wharton, in the clinker for his hideous behavior, and Delacroix, whose death is the centerpiece of this segment.

On the other side of the bars, Edgecombe is dealing with Percy Wetmore, a power-hungry prison guard with an itch to conduct executions. Percy gets the chance to play out his perverse games with Delacroix, but he bungles the job on purpose and makes the event memorable in unspeakable ways. It’s clear by the end of the tale that Percy has committed his last crime on the green mile (that final stretch of linoleum each prisoner must walk to get to the electric chair), but that there are still some surprises ahead for him. Edgecombe has formed an eerie conspiracy of guards and prisoners, but their purpose is still a secret — even to the reader.

Here’s a tip on the newest segment: When a horror writer uses the word “bad” before the word “death” in a title, he’s not fooling around. This is King at his goriest. You may find yourself saying “bleck” right out loud, and you certainly don’t want to read this one over lunch.

“Bad Death” gets off to a slow start, but picks up by the time Delacroix gets fried. Edgecombe reveals more details than we want to know about his private urges and discomforts, and he for sure tells us more graphic details than we want to know about Delacroix’s death. But Edgecombe has also become a convincing representation of a man from his generation and the voice through which King makes the requisite social commentary. The series is written as a catharsis for Edgecombe in his old age, and there’s no shortage of comparisons between his life in a nursing home and the lives of men on death row.

The series is selling outrageously well, and King has dominated the best-seller lists for several weeks. Among those readers represented on those lists, some are following along as the story unfolds and others are buying the books but holding off to read them as a whole. It is difficult to remember all the characters as the months pass, so if you haven’t started in yet, you might consider that option. However popular “The Green Mile” might be, it’s not consistently as engaging as King’s novels. Don’t worry, though. He and Richard Bachman have two books coming out in the fall. Save your book dollars for those.