Defending Jacob(105)

“On April 12, 2007, at around ten A.M., did you get a phone call about a murder in Cold Spring Park in Newton?”

“Yes, I did.”

“What did you do in response?”

“I went to the location, where I was met by Lieutenant Duffy, who gave me a briefing about what he had at the crime scene and what he wanted me to do. He brought me to the location where the body was lying.”

“Had the body been moved, as far as you know?”

“I was told it had not been disturbed since the police arrived there.”

“Had the medical examiner arrived yet?”

“No.”

“Is it preferable for the criminalist to arrive before the medical examiner?”

“Yes. The M.E. can’t process the body without moving it. Once the body is moved, obviously you can’t draw any inferences from its position.”

“Now, in this case you knew that the body had already been moved by the jogger who discovered it.”

“I did.”

“Were you able to draw any conclusions from the position of the body and from the surrounding scene nonetheless, when you first saw it?”

“Yes. It was apparent that the attack had taken place at the top of the hill by a walking trail and that the body had slid down the hill afterward. That was evidenced by a trail of blood leading down the hillside to the final resting position of the body.”

“These are the contact smears of blood we heard about yesterday?”

“Yes. When I arrived, the body itself had been rolled over face up, and I could see that the victim’s T-shirt was soaked with what appeared to be wet blood.”

“What significance did you attach, if any, to the large amount of blood on the victim’s body?”

“At the time, none. Obviously, the wounds were significant and fatal, but I knew that before I arrived.”

“But doesn’t the large amount of blood at the scene suggest a bloody struggle?”

“Not necessarily. Blood circulates through our bodies constantly. It is a hydraulic system: it is being pumped around and around. It moves through the circulatory system, through the veins, under pressure. When a person is killed, the blood is no longer under the pressure of a pump and its movement is then controlled by the ordinary laws of physics. So a lot of the blood that was apparent at the scene, both on the victim himself and on the ground underneath and around him, might have simply drained out of him because of gravity, because of the way the body was lying: feet above head, facedown. So the blood on the body might have been postmortem bleeding. I could not tell yet.”

“Okay, so what did you do next?”

“I examined the scene more closely. I observed some blood spatters near the top of the hill, at what seemed to be the point of the attack. There were only a few spatters here.”

“Let me stop you there. Is there a discipline in the forensic sciences of blood spatter analysis?”

“Yes. It is the study of the patterns of blood spatters, which can yield useful information.”

“Were you able to get any useful information from the blood spatters in this case?”

“Yes. As I was saying, at the point of attack there were a few very small blood spatters, less than an inch in size, and it was apparent from their size that they had fallen more or less straight down to the ground, spattering evenly in all directions. That is called a low-velocity drop or sometimes ‘passive bleeding.’ ”

Logiudice: “Now, yesterday we heard some discussion by the defense about whether you could expect to find blood on the attacker’s body or on his clothes after an attack like this one. Based on your observations of the blood spatters, do you have an opinion about this?”

“Yes. It is not necessarily true that the attacker here would have blood on him. Going back to the circulatory system that pumps blood through the body: remember that once blood is ejected from the body out into the air, it is subject to the ordinary laws of physics just like anything else. Now, it’s true, if an artery is cut, depending where it is on the body, you would expect the blood to gush out. That’s called ‘arterial gushing.’ Same with a vein. But if it’s a capillary, you might see just dripping like this. I did not see any spatters at the scene that seemed to have been cast off with force. That sort of cast-off blood would land at an angle and spatter unevenly, like this.” She demonstrated by sliding her fist along the length of her forearm to show how the blood drop would spread across the surface at impact. “It is also possible that the assailant stood behind the victim when he stabbed him, which would put him out of the trajectory of any spraying blood. And of course it is possible the assailant changed his clothes after the attack. All of which is simply to say that you cannot automatically assume that the assailant in this case would be covered in blood after the attack despite the large amount of blood found at the scene.”

“Are you familiar with the saying ‘The absence of evidence is not evidence of absence’?”

“Objection. Leading.”

“He can have it. You can answer the question.”

“Yes.”

“What does that saying mean?”

“It means that, just because there is no physical evidence proving a person’s presence at a particular time and place, you cannot necessarily conclude that he was not actually there. It’s probably easier to understand if I put it this way: a person can be present at a crime and leave no physical evidence there.”