Is the owner of the apartment complex liable if I was severely injured during a home invasion?

There are a number of issues that determine if the landlord may be held liable for the criminal acts of a 3rd party starting with the question of the number of prior break-ins and/or assaults on the premises. How did the assailant get a pass key? Was there negligence involved in his getting a key? Did the assailant live on the premises? Did he have a criminal background that management was aware of? Are there security cameras on the premises? Was there a history of tenants complaining about the lack of security, and/or lack of safety locks? Was there a history of prior break-ins? Were police officers called to the premises previously? How often? You may or may not have a case against the landlord based upon all of the facts. Impossible to generalize without knowing all the details.

Generally the landlord is not liable for the intervening criminal acts of another. There are exceptions so speak with an attorney with the details.

Perhaps, if the complex was negligent in allowing the pass key into the wrong hands.

The first proof obstacle you will have to overcome is whether the intruder did in fact use a pass key, or whether the door was inadvertently left unlocked. As there would be no damage to the door either way, it is not an insignificant issue. Discuss this matter with counsel of your choice.