If you are physically attacked at an apartment complex, it is true that when police are alerted, they will launch an investigation, determine if a crime was committed, and possibly file charges and work with prosecutors in pursuit of the alleged perpetrator(s). However, that is an entirely separate issue from whether you can pursue civil damages. Criminal matters are spearheaded by prosecutors, who must prove beyond a reasonable doubt that the attacker committed the alleged offense(s). The criminal court may even order the attacker to pay you restitution. But that is not the same as a third-party civil claim.
A civil claim for damages following an attack at an apartment building is something you would initiate by filing a lawsuit against the apartment owner, security company, and (in some cases) directly against the attacker. Your claim will assert the defendant's liability for damages stemming from your physical and psychological injuries that occurred in the attack.