I can think of one idea... injecting a syringe full of air could do that.
Oh I forgot that....yep. Was in the hospital when the IV tubing disconnected from the needle....they were worried I had gotten air in my veins! I was lucky and did not....instead all the blood was pouring out of my vein because I woke up wet....and walked from the bed to the nurses station making a big mess! Yes, too bad they did not look for a needle mark. Do they routinely take pictures of deceased bodies? Especially when there is no obvious causes, such as cancer? Probably not, but I was thinking out of the box.