Federal officials have charged a fourth man in connection with last week’s marijuana field shootout that killed El Dorado County, CA, sheriff’s Deputy Brian Ishmael , saying the new defendant was part of a conspiracy run out of Mexico that oversaw two marijuana grows in rural areas of Somerset and Georgetown.

Jorge Lamas, an American citizen who has spent much of his time living in Mexico, has been charged in a criminal complaint filed in federal court in Sacramento with conspiracy to manufacture, manufacturing at least 50 marijuana plants and possession of a firearm in furtherance of a drug trafficking offense.

The weapons charge stems from the discovery of a 9 mm handgun believed to have been the weapon used to kill Ishmael at a grow site in Somerset, the Sacramento Bee reports.

Lamas is believed to have been the foreman overseeing that site, as well as a separate marijuana growing operation in Georgetown, federal court documents say.

“After his arrest, Lamas was interviewed by law enforcement officer,” an affidavit from U.S. Drug Administration Task Force Officer Dave Stevenson says. “Lamas admitted to participating in a marijuana cultivation conspiracy that was run out of Mexico.

The use of smaller grow sites on private lands rather than the traditional use of huge pot grows in isolated National Forest lands is a trend that law enforcement sources say has been growing since California voters legalized recreational marijuana in 2016.

That is the situation officials believe Deputy Ishmael ran into in the early-morning hours of Oct. 23 as he was responding to a 911 call from an individual on Sand Ridge Road in Somerset reporting that someone was stealing his marijuana plants.

Ishmael and an off-duty San Joaquin County sheriff’s deputy responded just before 1 a.m. and spoke to the man who made the 911 call – identified by authorities as Christopher Ross – then went to the grow site and called for anyone in the field to come out.

Instead, someone opened fire from the field, striking Ishmael in the foot and in his chest above his bulletproof vest. The deputy died at the scene within minutes, and a deputy from another agency riding with Ishmael was wounded. Both deputies managed to return fire and wounded one of the suspects.

Juan Carlos Vasquez-Orozco, the alleged gunman, was charged with murder , assault with a deadly weapon and other counts in El Dorado Superior Court. Vasquez-Orozco is a Mexican national of unknown immigration status.

His alleged accomplice, Ramiro Bravo Morales, 22, was charged with being an accessory. Authorities say he also is from Mexico and had entered this country illegally about six months ago.

Ross, the man who called 911, was also charged with murder in El Dorado Superior Court after authorities say they discovered he had leased his land to the other two suspects to grow the marijuana but had not disclosed that to dispatchers or Ishmael after calling 911.

Instead, officials believe Ross called 911 because he was fearful the other men were going to harvest the 75 plants at the site and leave without paying him

The three suspects have pleaded not guilty.