Police received an anonymous 911 call from a tipster/victim who reported that an African-American male had pointed a gun at him and mentioned a gang name. The caller described the vehicle and described the man as having a cast on his arm. Dolly was stopped in a car which matched the description, and had a cast on his arm. A gun was found in the vehicle. After his suppression motion was denied, he was convicted of being a felon in possession of a firearm. The Court of Appeal affirmed the conviction, finding reasonable suspicion to justify the stop. The California Supreme Court granted review in this case to determine whether an anonymous 911 tip contemporaneously reporting an assault with a firearm and accurately describing the perpetrator, his vehicle, and its location is sufficient to justify an investigatory detention. The Court concluded that the Fourth Amendment does not bar police from taking necessary action to protect public safety under the circumstances of this case, and upheld the denial of the motion to suppress. There are situations where an anonymous tip provides sufficient indicia of reliability to justify an investigatory stop. Here, the tip was a firsthand report of violent criminal conduct requiring an immediate response to protect public safety. The call was recorded, and was fresh, detailed, and accurate. The motion to suppress was properly denied.