It took five days, but when officers arrested 26-year-old Luigi Mangione on forgery and weapons charges in connection with the murder of United Healthcare CEO Brian Thompson, the evidence was seemingly laid out for them on a silver platter.New York City Mayor Eric Adams told the public that Mangione was "in possession of several items that [they] believe will connect him to this incident."Police in Altoona, Pennsylvania, found Mangione with similar clothing, a face mask and the ID used at a hostel prior to the killing. They also recovered a firearm and a suppressor, both believed to have been used in the murder.Criminal defense attorney and former prosecutor Jeremy Saland called the evidence, as well as the apparent fingerprints matching items at or near the scene, "damning." RElATED STORY | CEO murder suspect Luigi Mangione expected to waive extradition to New YorkSaland added that this was an easy indictment for the Manhattan district attorney, but a less easy trial. In this case, it might not be about whether or not Mangione physically pulled the trigger; that much could be clear."There is an action and there's a mental state," Saland explained. "All that either goes to your case as the defense to challenge the mental piece of this, or even if it doesn't go that far to say to the prosecution it may not reach that legal threshold, but there's clearly something wrong here."Police also recovered a "mini-manifesto" reportedly directly connecting Mangione to the crime and railing against America's healthcare system. Saland says that could hurt an insanity defense."If you're premeditating this and planning it out step by step, and you're being articulate and reasoned as to why, even if it sounds weird or wrong or off base, it hurts that psychiatric defense. That said, you could still have mental health infirmities and defects, as we call it in the law, and pre-plan something and premeditate something," Saland said. "It doesn't preclude the defense, but it absolutely makes it much more difficult. This is a heavy lift. Have no misgivings, this is a heavy lift."Regardless, The insanity defense is one Saland says needs to be explored. He explained that Mangione's outburst after his arrest adds to the narrative that there is something mentally wrong with the 26-year-old.He is an Ivy League graduate and high school valedictorian with a seemingly stellar reputation. yet hadn't been in contact with family and friends for a significant amount of time. In fact, his mother called the police just over two weeks before the shooting."If she's reporting that he's been unstable and he's not been unresponsive, that helps explain who he is, that yes, he may have had the intent in terms of the eyes of the law, but he wasn't born from this malicious ugliness, even though his words may have reflected that it was born from this instability that he couldn't even control himself," Saland added.It's those little pieces that could put together a story for Mangione's defense team as they try to counter the growing mountain of evidence tying him to Thompson's murder.