Bombs, Bats, and Hammers

Consider these three cases together. Is the offered evidence relevant in any of them? Should it be admitted? Should its admission depend on anything else?

(1) Charge: assault with intent to commit murder. The state introduces evidence that the victim began to open an inner screen door of his trailer and an explosion took place. The state also introduces evidence that D had borrowed a clothespin from his friend the day before the explosion. The prosecution calls an expert on bombs and offers to have the expert testify using a model bomb to illustrate how a triggering device could detonate a charge of dynamite. The triggering device used in the model is a clothespin. The expert will testify that a clothespin was only one of a number of devices that might have been used to trigger the bomb and that the expert did not know what device was actually used. The expert will testify that a clothespin was used for the model only because it was easily available. D objects to the expert's use of the model and of the clothespin trigger and explains that he used the borrowed clothespin to attach a map to his car's dashboard. (When D was arrested in his car, a map was attached to the dashboard in this manner.)

(2) Charge: murder in the first degree. M.O.: battering the victim with a blunt instrument. The state's evidence establishes that the victim had over 20 fresh wounds on his body, some of which were consistent with injury inflicted by a blunt instrument such as a baseball bat or rolling pin, others that could have been made by the claws of a hammer, and some by the rounded head of a hammer. The murder occurred in the home shared by D and the victim. W, a friend of the defendant, testifies that, on the day the beating occurred, she found a baseball bat and a hammer under the bed in the room in which the body was found. W also testifies that she saw another person bring a second bat from the rear of the house to the bedroom. Both bats and the hammer had been removed from the house and disposed of by other persons. The prosecution produces a bat and a hammer. W testifies that they closely resemble the ones she found under the bed. The prosecutor offers the bat and hammer in evidence. D objects that the items are irrelevant and unduly prejudicial.

(3) Charge: murder in the first degree. M.O.: blows to the head during an alleged attempted robbery. A pathologist testifies that death was caused by chop wounds to the skull and brain from some sharp and heavy D was employed as a construction worker on a cleanup crew. The construction job involved dry-wall construction, in which a dry-wall hammer is generally used. Such a hammer has one round flat surface and one very sharp hatchet-like edge. No murder weapon was found but a framing hammer was found in D's car. The prosecution offers evidence that the victim's wounds could have been caused by blows from a dry-wall hammer. No such hammer was ever found, and it was never shown that D ever had one. The prosecutor borrows such a hammer from a worker in the courthouse. This hammer is identified, shown to the jury, and offered as evidence on the theory that it is illustrative of the testimony of various witnesses. D objects on grounds of irrelevancy and prejudice.

The evidence of these problems is fundamentally different from the direct testimonial evidence of a witness on the stand and the "real'' evidence in Adamson, Stone, and the T-shirt case. The clothespin, baseball bat, and hammer are all "demonstrative'' evidence. (Wigmore proposed "autoptic profferance'' as the more precisely descriptive term for such evidence.) In each case, there is no contention that the exhibit was actually used in the commission of the crime, or that the defendant had any connection with such evidence. Admission of such evidence thus must rest on some theory different from that used to admit the stocking tops, condoms, and T-shirts. The theory that supports the admission of this kind of evidence is that it aids the witness in describing what the witness saw or in explaining what happened.

The key issue usually is what foundation must be laid before use of the evidentiary aid will be allowed. Such exhibits can create a big impression on jurors, who may lose sight of the fact that the exhibit was not actually used in the real event.

How much leeway should a party have in choosing whether to prove a fact with a picture, a demonstration, or a real object when the testimony of a competent witness could prove the same? Recall the Lopinson case (Problem II-8). When is real evidence necessary to prove a fact? What is the effect of choosing one form of proof over another?

These questions involve sensitive considerations of probative value, prejudice, reliability, and, often, strategic choice. By and large, our adversary system employs a free market approach to the choice of evidence: Parties are free to prove a fact with any kind of evidence they like. But this free market is restrained by various rules of exclusion that limit parties' choice in certain circumstances. The rule requiring the production of the original document in certain cases (Rule 1002) is one example. Why do we have such a system? What are its advantages and disadvantages? An alternative system would contain a master list of types of evidence with a hierarchy of preference. In each case, the "higher" or "better" type of evidence would have to be used. This, no doubt, would promote certainty but at a great cost.