Draper v. United States
The Supreme Court upheld the warrantless arrest and search of a man found carrying heroin after federal agents confirmed, in person, every detail of a reliable informant's tip except whether he actually had the drugs.
The ruling established that police can rely on an informant's tip to establish probable cause even though the tip itself would count as inadmissible hearsay at trial, as long as officers independently verify enough of the tip to make it believable.
“In dealing with probable cause, . . . as the very name implies, we deal with probabilities. These are not technical; they are the factual and practical considerations of everyday life on which reasonable and prudent men, not legal technicians, act.”
The Court explains that probable cause is a practical, everyday standard, not a technical legal one.
How it got here: A federal trial court denied the motion to suppress and he was convicted; the Tenth Circuit affirmed; the Supreme Court granted review on the Fourth Amendment question.
The Case in Depth
What happened
A paid federal narcotics informant told an agent in Denver that a man named James Draper was dealing heroin and would return from Chicago by train on a specific morning carrying three ounces of heroin, giving a precise physical description. Agents watched the trains, spotted a man matching the description exactly, arrested him without a warrant, and found heroin and a syringe on him. He was convicted of drug trafficking and challenged the search that produced the evidence used against him.
The question before the Court
Could a federal narcotics agent lawfully arrest a man without a warrant based on a paid informant's detailed tip, once the agent personally confirmed every detail except whether drugs were actually on him?
Why it matters
The decision gave police broad authority to act on informant tips without first getting a warrant, so long as they corroborate enough details to make the tip credible. It became a foundational case for how courts evaluate informant-based probable cause in drug and other criminal investigations, shaping police practice for decades.
What changes now
This is a final merits decision with no remand; the conviction and the denial of the suppression motion stand. The heroin and syringe remained admissible evidence, and the ruling continued to govern how lower courts assess whether corroborated informant tips can supply probable cause for warrantless arrests in future cases.
What this does not decide
The Court did not decide that any uncorroborated tip from an informant is enough for probable cause; it stressed that the officer had personally verified nearly every detail of the tip before acting. It also did not address what happens when officers verify far less of an informant's information.
Concurrences and dissents
Dissent — Justice Douglas
“The arresting officers did not have a bit of evidence, known to them and as to which they could take an oath had they gone to a magistrate for a warrant, that petitioner had committed any crime.”Douglas's core objection that officers acted solely on an informant's unverified word.
Justice Douglas argued that an arrest based solely on an informant's unverified word, without any independent evidence of guilt known to the officers themselves, violates the spirit of the Fourth Amendment and the narcotics arrest statute. He traced the historical fight against arrests on mere suspicion, from English general warrants to French lettres de cachet, arguing officers here could not have gotten a warrant from a magistrate on this information alone, so they should not get more leeway by skipping the warrant altogether.
How the Court got there
The legal reasoning, step by step
- The Court framed the question as whether the agent had 'probable cause' under the Fourth Amendment and 'reasonable grounds' under the federal narcotics arrest statute to believe the man was committing a drug crime, since a lawful warrantless arrest would make the following search of his person valid as incident to that arrest.
- The Court rejected the argument that information could not count toward probable cause simply because it would be inadmissible hearsay at a criminal trial, explaining that the amount and type of proof needed to show probable cause is much lower than what is needed to prove guilt at trial.
- Applying that standard, the Court reasoned that once the agent personally verified nearly every specific detail the informant had provided — the exact clothing, the tan bag, the train, the timing, even the man's fast walking pace — it was reasonable for the agent to also trust the one unverified detail, that the man was carrying heroin.
- The Court applied the general probable-cause test asking whether the known facts would lead a reasonably cautious person to believe a crime was being committed, and concluded that the level of corroboration here comfortably met that bar.
- Because probable cause existed, the warrantless arrest was lawful, which meant the search of the man's person immediately following the arrest was also valid as incident to that lawful arrest.
Doctrinal impact
Cases affected by this decision
Reaffirms Brinegar v. United States (338 U.S. 160)
Reaffirmed that evidence too weak or inadmissible for trial can still establish probable cause for an arrest.
Reaffirms Carroll v. United States (267 U.S. 132)
Reaffirmed the standard that probable cause exists when known facts would lead a reasonable person to believe a crime occurred.