What could be in the mind of a mass shooter? That's what many are asking after 17 people were killed in last week's school shooting in Florida.
We are learning more about the accused gunman Nikolas Cruz. He and other alleged mass shooters may have something in common.
That's according clinical psychologist Judy Malinowski of the St. John Providence health system.
"Perceived sense of injustice and they always feel like the world is against them."
She and other psychologists study the minds of mass shooters, trying to figure out what makes them pull the trigger. Judy says many have a sense of revenge. Other are withdrawn, have outbursts of anger and do not have the ability to deal with emotions.
One key factor is lack of empathy.
"I have to literally block off my ability to understand how your are going to feel if you are in pain," Malinowski explained.
Many mass murderers, Judy says are men, and psychologists are still trying to find a clear answer as to why.
"How genetically we are dealing with certain pressures within us, how women's brains might be different, how we deal with our emotional states."
Malinowski says it's important not to ignore red flags.
In last week's shooting, the suspect was known to have a disturbing social media presence. Psychologists says those should be considered cries for help.
"Whether it's getting obsessive with guns, whether it's posting things, whether it's journaling out, talking to people about it."