You are an investigator called to the scene of a suspicious incident at a private residence. Once on scene, you are told by the initial responding patrol officer that a male complainant, who does not reside at the residence, came to the residence to look for his wife who he last saw the evening before. When he arrived, he did not get an answer at the door, so he looked through a window and observed blood and multiple shell casings on the floor, so he called 911. Officers forced entry into the residence and confirmed a large amount of blood and shell casings in various rooms throughout the home. They did not locate any victims, so they have he exited the home.
The husband was interviewed by officers prior to your arrival, and he told officers that his wife has a drug addiction, and he believes she came to the residence the evening prior to purchase drugs. She never returned home, so he decided to come to the residence today to see if he could find her. The husband then provided officers with his wife's name, date of birth, and her vehicle license plate and vehicle description since the vehicle was not located at the residence. There was one vehicle in the driveway, but it's unknown who it belonged to.
A canvas of the neighborhood by initial officers revealed the residence in question is occupied by an older lady who resides on the first floor of the residence and rents the lower level of the residence to a male who has an elementary age child. Again, no one was in the residence when the initial officers conducted a preliminary sweep of the residence.
You have been designated as the primary homicide investigator on this case and are responsible for all aspects of the investigation. As a result, answer the below questions.

Discuss how you would navigate search and seizure considerations before beginning your crime scene processing.