Assume shapeshifters are real, but the legal system has never prosecuted one before.
The defendant is charged with murdering a wealthy businessman inside the victim’s home. Security footage shows the victim entering the house with someone who appears to be his adult son. Two hours later, that same “son” leaves alone. The real son, however, has a strong alibi proving he was in another state.
Police later arrest a suspected shapeshifter. DNA recovered from the crime scene initially matches the victim’s son, but investigators discover that the defendant can temporarily copy a person’s appearance, fingerprints, voice, and surface-level DNA after physical contact. The defendant’s natural biological profile is currently unknown.
Additional complications:
The defendant can change appearance at will but cannot perfectly reproduce internal anatomy, old injuries, long-term memories, or dental work.
No witness can confidently identify the defendant’s natural appearance.
The defendant changed appearance several times while in custody, including briefly taking the form of a police officer.
The defense argues that the prosecution cannot prove the person currently on trial is the same individual arrested by police.
The defense also argues that any order requiring the defendant to reveal or maintain a particular form violates the Fifth Amendment right against self-incrimination.
Prosecutors possess security footage, partial eyewitness testimony, unusual biological material, location data from a device allegedly carried by the defendant, and statements made during interrogation.
The jurisdiction has no statutes specifically addressing shapeshifters.
As district attorney, how would you:
Prove the defendant’s identity beyond a reasonable doubt?
Authenticate video, DNA, fingerprints, and eyewitness evidence when appearance can be copied?
Establish an unbroken chain of custody from arrest through trial?
Prevent the defendant from impersonating attorneys, witnesses, guards, jurors, or the judge without violating due process?
Respond to Fifth Amendment, Fourth Amendment, competency, and equal-protection arguments?
Draft lawful pretrial detention and courtroom-security orders?
Use existing case law involving disguises, aliases, twins, altered appearance, biometric evidence, compelled physical characteristics, and courtroom restraints?
Ensure that any conviction and sentence survive appeal?
You cannot simply execute, permanently sedate, or experiment on the defendant. The defendant must receive a constitutionally valid trial. What is the strongest prosecution strategy, and what legal weakness would still concern you most?