WASHINGTON:A Colorado man who allegedly killed five people this week had self-published novels in which the main character shoots people very similar to his real victims.

The shooter, identified by police as Lyndon McLeod, was shot and killed by police after Monday's massacre.

"We are aware of the books written by the suspect under a pseudonym, which are a component of our investigation," a spokesperson for the Denver police department confirmed to AFP Thursday.

McLeod wrote a trilogy called "Sanction" between 2018 and 2020, under the name Roman McClay.

On photos posted to his social media accounts, McLeod has a long beard, brown hair, and tattoos across his neck and chest.

The plot of the series is described in an online review as following "a politician/billionaire (who) wants to use gene editing tech to rewrite the DNA of criminals. Think serial killers and just generally violent people."

According to US media reports, McLeod wrote in his first book about a character named Lyndon MacLeod, who goes on a mass rampage, killing 46 people in one night.

The first person the character kills is a former business associate named Michael Swinyard, in an apartment in Denver.

Denver authorities confirmed that one of McLeod's real victims had that name and lived at the same address as in the book.

In another volume, the author describes the murder of a woman named Alicia Cardenas -- the same name as a woman killed on Monday night.

McLeod's name is also mentioned in legal documents for a building purchase made by Cardenas a few years ago.

In a post on his website, "Roman McClay" says that he likes to "use real names and real events and real people alongside fictional ones" in order to "blur the line between what is and what is possible."

On Monday, the 47-year-old man first opened fire at a tattoo parlor in Denver, killing a tattoo artist and the salon's owner, Alicia Cardenas.

Next, he killed Michael Swinyard in his apartment and then traveled to Lakewood -- suburb of Denver -- where he killed another man in a tattoo parlor and then a hotel receptionist.

Shortly afterword, he was approached by police agent Ashley Ferris, whom he shot in the stomach, before she returned fire, killing him.

"It appears there were personal and/or business-related connections between the suspect and the victims," the police spokesperson told AFP.

In a press conference Tuesday, police said that McLeod did not necessarily know the hotel receptionist, but did have "previous interactions with that hotel."

He had previously been under investigation in 2020 and 2021, but no charges were filed, said police, who have yet to determine a specific motive for these attacks.