Los Angeles County Sheriff Robert Luna revealed on Friday that one of the two grenades located at a Santa Monica townhome complex right before an explosion that resulted in the deaths of three deputies is currently unaccounted for.

On the day before the blast, the sheriff’s department’s Arson and Explosives Detail teamed up with Santa Monica police when a resident discovered “two grenade-like devices” in a storage area within an underground garage. Luna explained that although initial x-ray examinations suggested the devices were “inert,” they were still taken 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 eliminate the possibility of another person’s involvement and stated that his department, along with its partners, is investigating anyone who could be linked to the incident. However, he did not disclose how many suspects are under investigation.

“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.