Some thoughts so far as to this shooter, possibly imo:
(SPECULATION, JMO, MOO)
1. Has previous or current gang affiliations, and/or is a "wannabe gangsta".
2. Has been arrested for prior crime (s) such as robbery, vandalism, DV, assault, drugs, guns, carjacking, motor vehicle theft, bank robbery, convenience store robbery.
3. Has prior military experience, possibly has been dishonorable discharged (served overseas?).
4. Has suffered the loss(es) of a loved one (via violence?)(younger sibling?)
*maybe lost his mother or grandmother (natural causes?).
5. Has possible affiliation with radical political group, such as ISIS; possible recruit.
6. Deals in narcotics, prostitution (Nebraska Ave.).
7. Has a geographic connection to the area, past or present via work, family member or prior residence, school, etc. (Anchor point, geographic profiling, awareness space, Rossmo)
8. Has a history of playing violent video games.
9. Possible struggles re: sexuality considering victimology if not random.
10. Drug user.
11. Deals guns.
12. History of sexual assault.
13. Has shot up structures before, buildings, vehicle windows, joyride style.
14. Possibly lives with elderly relative.
15. Has small kid (s) and possible dysfunctional relationship with baby's mother(s). Deadbeat dad.
Moo. It will be interesting to see how close or far this speculation this. I do not see some law abiding citizen with no prior violent history that nobody would suspect as this shooter. Of course I could be way wrong!
Psychologically:
1. Confident his athletic abilities and ability to escape/outrun LE and others.
2. Severe detest towards Law Enforcement.
3. Enjoys inflicting fear in community.
4. Densensiitized to violence and death.
5. Revels in his sense of power and control. Thinks he's smarter than everyone else.
6. Consumed by an overwhelming urge/compulsion to continue killing, similar to a SK, almost like an addiction.
*I lean more towards a disorganized offender:
"The disorganized offender is usually of low-average or below average intelligence. They often have poor work ethic and are apt to be regularly fired from or reprimanded at work; in the cases where a disorganized offender has a steady work ethic, they work blue collar jobs or jobs which require little or no use of reasoning or intelligence. They are socially inadequate and possess little or no interpersonal skills; most disorganized offenders have never been married or in a serious relationship. Although a disorganized offender may claim to beheterosexual, evidence will usually suggest that they are either a virgin or that their sexual conquests have come in relation to a paraphilia, such as necrophilia, bestiality, or pedophilia. Some disorganized offenders have exhibited homosexual tendencies, but in such cases, any homosexual contact they may have had will usually be either as a symbolic act of dominance or as an offshoot of one of their paraphilias. They most often live alone or with a family member.
Disorganized offenders have an innate fear or anxiety in regard to people, especially strangers, and usually live in a complex delusion that they have constructed in their own mind. Ed Gein, for example, exhumed the corpses of women who he believed reminded him of his mother and consumed parts of them because he believed that he could preserve his mother's soul inside of his own body, going so far as to create a "female suit" made of human flesh that he would wear when assuming his mother's identity.
Disorganized offenders,[2] lacking confidence and the skills necessary to plan a crime, do not venture far from their homes when committing murders. Their victims are either chosen at random or are people they know personally. The murder is violent, brutal, and sadistic; the disorganized offender uses overkill. A disorganized offender may stab his victim dozens of times even after he or she is dead."
https://en.m.wikipedia.org/wiki/Disorganized_offender