In the example of assault by strangulation, what marks did officers observe on Justin?

In the context of an assault by strangulation, the presence of red marks around the neck is a critical symptom that indicates an attack involving restricted blood flow or breathing. These marks are typically a direct result of pressure applied to the neck during the strangulation process. The redness signifies trauma to the skin and underlying tissues, which can often be observed immediately following such an incident. This evidence is crucial for both medical evaluation and any potential legal proceedings, as it provides clear, visible signs of the assault that can corroborate the victim's account of the event.

Other options, while they may suggest physical altercations or trauma, do not specifically relate to strangulation. Bruises on the arms or cuts on the forehead might suggest different forms of assault, but they do not indicate the specific mechanism of injury related to strangulation. The absence of visible injuries altogether does not provide any evidence of strangulation, making red marks around the neck the most relevant and telling sign in this scenario.