DENVER (KDVR) — Lyndon McLeod wrote a book called “Sanction” detailing some of the events that unfolded during Monday’s deadly shooting spree. That book, which was self-published in 2018, mentions some of the killer’s victims by name.

But, as officers from Denver and Lakewood continue to follow leads, it’s unclear if they knew about what was written.

Denver police told FOX31 the shooter was known to law enforcement, but they wouldn’t say exactly how or to what extent just yet.

“It comes down to what you know, when you know it,” said retired Colorado police officer James Allbee.

It’s unknown if officers were aware of a book, which appears to have been published as fiction but reads like a kill list manifesto. If they were, what would or could they have done legally? Were those named notified? These are questions the FOX31 Problem Solvers asked police agencies on Monday.

“Did the investigators, assuming that they had knowledge of this book and that these threats were being made, did they believe that these were actually real people?” Allbee said.

A Lakewood police spokesperson said Monday, “To my knowledge, our department had never been aware of a book written by the suspect. We, like DPD, are looking into all leads in this case as it unfolds. The suspect had never been arrested in Lakewood.”

The Aurora Police Department said it was also unaware of McLeod’s book despite officers there being mentioned in his book.

Allbee said it’s important to remember that those who feel threatened, even if it doesn’t rise to the level of police being able to make an arrest, should still report unsavory behavior.

“That would be a great opportunity to reach out and get civil protection order for cases like this,” he said.

Although such an order may not have helped in this case, it may help in other cases where victims can create a paper trail that allows police more flexibility moving forward.

FOX31 asked DPD if they were aware of the book prior to Monday and if anything could’ve been done differently. Late Wednesday afternoon, Denver police sent the following emailed statement to FOX31:

“Regardless of the fact that the suspect in these homicides is deceased, we have an obligation to conduct a thorough and complete investigation. As Chief Pazen mentioned yesterday, there were two separate investigations involving Lyndon McLeod in 2020 and early 2021. The investigations did not result in charges. Any prior investigations involving Lyndon McLeod are part of the current homicide investigation. Because the investigation is active and ongoing, additional information is not available for release, at this time.”