LAKEWOOD, Colo. (CBS4) – As family and friends mourn the loss of their loved ones to a deadly shooting spree that spanned from Denver to Lakewood on Dec. 27, questions about the gunman are mounting.

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“This is really upsetting to a community,” Rep. Ed Perlmutter said.

He is one of four Congressional leaders, including Representatives Jason Crow (CO-06), Diana DeGette (CO-01) and Joe Neguse (CO-02), who sent a letter to the U.S Department of Justice requesting an investigation into the handling of prior law enforcement encounters with the presumed gunman, Lyndon McCleod.

In part the letter states: “We have serious concerns regarding the sharing of information and the response of law enforcement officials and whether it was adequate, timely and thorough.”

RELATED: Police Say Lyndon McLeod Knew 4 Of 5 Victims Killed In Shooting Spree, Was ‘On The Radar’

Mcleod is believed to have targeted most of his victims and published a book depicting himself carrying out a shooting in Denver that included the names of those who were murdered.

(credit: CBS)

“This individual was known to law enforcement he was on our radar,” Denver Police Chief Paul Pazen said at a press conference the day after the shooting.

He confirmed there were at least two previous investigations into the gunman but say neither of those resulted in criminal charges.

“I don’t want to throw mud at the Denver police or the FBI or any other agency, this is more of a process thing because we have seen this before,” Perlmutter said.

The goal of the letter he says is to better understand what happened and do more to keep it from happening again.

“Is there good information-sharing among different police departments and agencies like the FBI and Homeland Security or are there too many silos,” Perlmutter said, “When do you let someone off the radar screen?”

The Denver Department of Public Safety responded with the following statement, “The Denver Department of Public Safety is conducting its own review of the January 2021 investigation into Lyndon McLeod and will fully cooperate if the Department of Justice initiates an investigation.”

Karen Morfitt