Explosives and a marijuana farm were discovered at a Southern California home doubling as a state-licensed child day care center after a man blew off four of his fingers while mixing homemade explosives, authorities said Thursday.

Benjamin Kuzelka, 23, remained hospitalized at Loma Linda Medical Center and will be arrested when he his discharged, said sheriff's Sgt. Dennis Gutierrez. His mother, Rebecca Kuzelka, 55, and brother, Greg Kuzelka, 21, were booked Thursday on suspicion of manufacturing illegal explosives, illegal growing of marijuana and child endangerment, he said.

Authorities went to Kuzelka Family Day Care after a local hospital reported late Wednesday that Kuzelka walked in and said he had shot himself in the hand. Doctors, however, became suspicious because the wound was inconsistent with a gun shot injury and they called authorities, Gutierrez said.

Investigators found explosives, a sophisticated marijuana-growing facility and evidence that the home had been used as a state-licensed child care facility as recently as the day before, Gutierrez said. The home is on a cul-de-sac in a remote area of Riverside County about 70 miles southeast of Los Angeles.

"We do believe that when all this illegal activity was going on, that children were present," he said. However, no children were home at the time of the explosion, authorities said.

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The explosives were hidden outside and detectives believe Grey Kuzelka moved them from the garage to the backyard while his brother was seeking medical treatment, said sheriff's Sgt. Pat Chavez.

A hazardous device team responded to the scene and defused explosives Thursday in several controlled blasts throughout the day. They left the scene by the late afternoon, Gutierrez said.

The FBI, which is also investigating, said there was no immediate indication that the case was linked to any terrorist investigation or any threat to public safety.

FBI spokeswoman Laura Eimiller referred all other questions to Gutierrez, who said he did not know what types of explosives were found at the site or how powerful they were.

Grey Kuzelka had been arrested on Saturday for investigation of possessing marijuana and concentrated cannabis, and was released the next day on $5,000 bail. Riverside County court records show Benjamin Kuzelka has a string of convictions for drunken driving and drug possession dating back several years.

A child care advocate with the state's community licensing division, which awards day care licenses, did not immediately respond to an e-mail or phone message seeking comment.

The facility was licensed for children ages 2 to 5 and was approved for no more than eight children at a time, Chavez said.

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