In what circumstances have the courts accepted an anonymous tip from a minor as a basis for probable cause?

We have accepted anonymous tips as a basis for probable cause where significant details of the tip were corroborated. See, e.g., United States v. Rodriguez, 869 F.2d 479 (9th Cir.1989); United States v. Fixen, 780 F.2d 1434 (9th Cir.1986). However, in the present case there are no details to corroborate; the tip consisted only of a bald assertion that the crime was occurring at a certain place.

A tip similar to this one was given to the police in United States v. Kerr, 876 F.2d 1440 (9th Cir.1989), in which an anonymous informant told police only that the defendant was growing and distributing marijuana. Although the tip itself contained no detail that could be corroborated to show the reliability of the informant, we agreed that probable cause had been established. This conclusion was based in part on the fact that, subsequent to receiving the tip, police investigation "revealed several additional facts which, although relatively innocuous on their face, tend[ed] to corroborate the informant's story," including the fact that the investigating officer smelled the odor of marijuana at the defendant's home. ¹⁰ Id. at 1444.

Similarly, in White by White v. Pierce County, 797 F.2d 812 (9th Cir.1986), we upheld a warrantless entry by police officers dispatched to the plaintiff's residence because of a report that a seven-year-old child with severe welts on his back was seen playing in the yard. While the officers were speaking with the plaintiff, they saw a boy who appeared to be about seven years old trying to show them his back. When the plaintiff told the boy to go to another room and refused to let the officers see the boy, the officers entered forcibly and examined the boy. Id. at 814.