As the community of Parkland is reeling from a horrific week, officials are gaining new insight into the mind of the shooter. 

Officials say they have found group chat messages showing Nikolas Cruz was obsessed with race, violence, and guns. At one point reading, "I hate Jews, n-words, immigrants." 

Cruz also talked about killing Mexicans, keeping black people in chains, and cutting their necks. 

Broward County Sheriff Scott Israel said the sheriff's office has received over a dozen calls about Cruz. 

"We have uncovered at the Broward County Sheriff's Office that we've had approximately 20 calls for service over the last few years regarding the killer," Sheriff Israel said. 

Police documents show his mother had repeatedly called officers to the home. 

Some incident reports, as recent as September 2016, described the shooter as suffering from mental illness and being "emotionally handicapped."

However, none of it was enough to stop him from passing a background check and buying an AR-15 semi-automatic rifle. 

The FBI said they received a tip from someone close to Cruz saying they were concerned about his violent tendencies. 

"The caller provided information about Nikolas Cruz and the potential of him becoming a school shooter," said Robert Lasky, Special Agent in Charge, FBI Miami Division.

The FBI never acted and according to FBI Director Christopher Wray, the information was never relayed to the Miami Field Office.

Meanwhile, the Parkland community is trying to heal as they bury classmates, sons, daughters, friends. 

And even as the days pass, the memories of what happened are still as vivid as ever. 

"We all ran back when we heard gunshots and we were there for the rest of the time. A girl behind me was crying, I wanted to calm her down," said 9th grader Braden Freidkes. 

The mayor said the school district plans to tear down the building where the shooting happened, but even as the physical reminder of the pain goes down, the emotional ones will last a lifetime. 

Nikolas Cruz is expected to appear in court Monday, Feb. 19. Officials say he is willing to plead guilty in order to avoid the death penalty and spare the community from re-living the massacre in a trial. 

Interactive timeline: Parkland shooting