Can you sue a city district attorney office

I was a police officer for 9 years. I was involved in a on the job shooting with a suspect who had kidnapped 3 people. He shot a me I shot at him. He got away. Car jacked anther person and hurt her. Wrecked out their vehicle and still got away. DNA was obtained from the shooting suspect and was identified. District attorney knew who the suspect was but would did not prosecute for attempted capital murder of a police officer. Same suspect was arrested 2 years later in another county for organized criminal activity home invasion and there he has sit since with prosecution. The investigators have pleaded with this large city to prosecute and they will not. No the suspect if they tried to prosecute would be denied due process. My question is it pisses me off. I was doing my job and the city district attorney did not have my back. I early retired two years later because I just could do the job anymore after that incident I had medical issues. Do I have a case?