GARDENA (CBSLA.com) — Two South Bay residents were arrested on suspicion of making many fraudulent 911 calls over a six-month period, police said Tuesday.

Michael Sumolang, 27, of Torrance and Corey Jackson, 28, of Gardena are accused of making as many as 20 fraudulent calls together and then watching from a distance as emergency personnel responded. They were arrested March 10.

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The calls are part of a worrying trend for law enforcement called “swatting,” in which fake calls are made to elicit a response from Special Weapons And Tactics officers.

“On face value, it looks like they truly enjoyed it,” said Gardena Police Department Lt. Russ Temple. “It’s extremely frustrating that people can be so careless.”

In the Feb. 27 call that kicked off the police investigation, a man told a police dispatcher he had just witnessed a woman getting shot in the chest by her husband, who was possibly an off-duty LAPD officer. The caller told the dispatcher that the “shooter” was arming himself for a standoff with police.

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A large number of police and fire department responded to the address, where a family was asleep inside. It was the third time their house had been targeted by “swatters.”

Investigators said 20 such calls were made to five South Bay police agencies, including in Gardena, Torrance, Hawthorne, El Segundo and Hermosa Beach, in recent months. The California Highway Patrol also received similar calls to dispatch, including one specific call where the caller threatened to harm an officer.

Both suspects admitted to making the fictitious calls together, police said.

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The Los Angeles County District Attorney’s Office has charged Sumolang and Jackson with felony counts of reporting a false emergency.