Celebrity 'swatters' beware: Cops are closing in Rihanna Celebrities targeted by fake 911 calls recently would fill a Hollywood red carpet A proposed law would increase penalties for making false emergency calls Police are getting new tools for tracing swatting calls, sheriff's spokesman says "We're getting better at knowing what is and what isn't a hoax," he says Los Angeles (CNN) -- "Swatting" pranks have sent police rushing with guns drawn to a growing A-list of celebrity homes in recent weeks, but new tactics, technology and a proposed law could bring the dangerous hoaxes to an end. Russell Brand's Hollywood Hills home was the latest target Monday afternoon. A 911 caller told a Los Angeles Police Department emergency dispatcher that a man with a gun was in the house. "A number of officers from the Hollywood Division" were sent to Brand's address, LAPD Detective Gus Villanueva said. To get to Brand's home high above Sunset Boulevard, police cruisers sped up the narrow, winding street past the homes of Halle Berry, Herbie Hancock and many other celebrities. Officers must approach the scene with guns drawn, not knowing what is happening inside the house and expecting the worst. "It's a very high-risk response," Los Angeles County sheriff's spokesman Steve Whitmore said. The problem with crying wolf is that sometimes it's not false, so we always have to respond accordingly but cautiously. Among the LAPD, the Sheriff's Department and other local agencies in the Los Angeles area, it has happened about a dozen times in recent months. The actors and musicians targeted would make an impressive red carpet: Rihanna, Justin Timberlake, Miley Cyrus, Chris Brown, the Kardashians and Tom Cruise. A 12-year-old boy was sentenced to two years in juvenile detention after he admitted last month that he made fake emergency calls that sent police to Ashton Kutcher and Justin Bieber's homes last October. "The comments of the call advised that there were individuals inside the location with guns and explosives, and that several people had been shot," a police statement said. Boy admits 'swatting' Kutcher, Bieber Dozens of emergency personnel rushed to Kutcher's home on October 3, 2012, only to find workers inside and no emergency, police said. Kutcher, who was on the set of his TV sitcom "Two and a Half Men," also rushed to his home. Catching swatters who spoof a telephone number so that an emergency dispatcher thinks a call originated from a celebrity's home will get easier as technology and tactics improve, Whitmore said. These prank calls earned the nickname "swatting" because law enforcement agencies sometimes would send SWAT teams to respond to the false emergencies. Law enforcement agencies are "making advances each day" in their ability to track the calls to their origin, he said. Along with new technology, investigators have analyzed the calls to learn how to identify them. "We're getting better at knowing what is and what isn't a hoax," he said. When Rihanna's Hollywood Hills home was swatted last week, the dispatcher suspected it was a hoax, so just one police patrol car was initially sent, LAPD Cmdr. Andrew Smith said. "We figured it was a swatting," Smith said "We really low-keyed it compared to how we've been." LAPD officers are being trained on "what to be aware of and the possibility these are swatting calls," Smith said. We're training dispatchers to be able to recognize certain distinct characteristic of these calls and maybe change the way we dispatch them so they don't draw as high a profile response. The rash of swatting incidents spurred the sheriff and other law enforcement chiefs to push for tougher penalties for those convicted, Whitmore said. California state Sen. Ted Lieu has introduced legislation to require a mandatory 120 days in jail for anyone convicted of swatting, Whitmore said. The swatter would also have to repay police for all costs, which would probably be several thousand dollars, he said. "This is not a panacea, but a step in the right direction," the sheriff's spokesman said. Lieu, whose Los Angeles district covers some of the celebrity homes targeted, held a public hearing on his proposal at the California Capitol in Sacramento on Tuesday morning.