Los Angeles County Sheriff Robert Luna announced Friday that one of two grenades found in a Santa Monica townhome complex prior to an explosion that killed three deputies is currently missing.

The day before the explosion, members of the sheriff’s department’s Arson and Explosives Detail assisted Santa Monica police after a resident reported finding “two grenade-like devices” in a storage unit in an underground garage. Luna said the devices were believed to be “inert” after an x-ray but were still transported to the Biscailuz Center Training Academy to be “destroyed and rendered safe.”

An explosion at a Los Angeles County Sheriff’s Department training facility left three deputies dead. (KTTV)

The sheriff did not rule out the possibility of another individual being involved and said his department and partners were investigating anyone potentially linked to the tragedy, though he did not specify how many suspects there might be.

“I am not ready to discuss here and now any names of any individuals that may be people of interest or anything of that nature, not yet,” Luna told the press.

Los Angeles County Sheriff Robert Luna speaks during a news conference after an explosion at a training facility killed three deputies on Friday. (Pool/Fox News)

Luna emphasized that the ATF’s findings are preliminary but said the agency expects to complete its final analysis within 45 days.

The July 18 explosion claimed the lives of Deputies Joshua Kelley-Eklund, Victor Lemus, and William Osborn. The three men were assigned to the Special Enforcement Bureau’s Arson Explosives Detail.