A Los Angeles County Sherriff's Department saw a Cessna 172 flying erratically and ordered it to land. It did so and the chopper followed it to the airport where the pilot was interviewed and perhaps issued a citation.
Can the FAA be far behind?
In the US, local law enforcement has concurrent jurisdiction with FAA to enforce safety of flight regulations as well as any laws the state has regarding flight safety operations. It is my impression that every state in the union has a law that prohibits operation of a/c while under the influence of alcohol or narcotics. Erratic flight would certainly create a reasonable suspicion that may be the case.
FAA regulations also allow local law enforcement officers to do ramp checks as if they were FAA inspectors. Not many do but they can. In most states, the burden for stopping a pilot on the ramp would be the same as for making a vehicle stop - there must be probable cause for the officer to believe a violation has occured.
In my career, I arrested two pilots for operating under the influence and one for unlawful possession of controlled substances. In the unlawful possession case, the county also seized the a/c, went to court, and the court forfeited the ownership of it to the county as is often done with motor vehicles and boats.
There have been several cases, all over the country, where commercial aircrews have been arrested by local law enforcement for being under the influence. There are also many cases where illegal or erratic operations in the air have been reported by citizens and local law enforcement helicopters or aircraft have interecepted the a/c and forced it to land for investigation.
If anything further makes the news, I'll post it. All I could find out is that the 172 belonged to a flying school. It was interesting to watch it all happen, live on TV. Maybe it will become more popular than watching high speed chases on the freeway.
What part of Los Angeles? And what time of day was it? I was most likely in school.