Harry Storch, Devin Edward Montgomery and Timmothy D. Gray, who Boise police say are members of the “Slayer” gang arrested earlier this year in connection with a series of violent robberies, have entered guilty pleas in their criminal cases.

That means 10 of the 11 members or affiliates of the “Slayers” arrested in June have entered guilty pleas, including the self-admitted “president” of the club, 53-year-old Jerry Brown.

The only remaining member who has not entered a guilty plea is Seth Kormylo. His upcoming trial has been delayed while a judge determines if Kormylo is mentally competent to understand the charges against him and can participate in his own defense.

The 32-year-old Montgomery pleaded guilty last month to delivery of a controlled substance (marijuana) and recruiting a gang member charges. Ada County prosecutors dropped charges of conspiracy to commit grand theft by extortion and aggravated assault as part of a plea agreement.

The 29-year-old Gray pleaded guilty earlier this month to charges of delivery of a controlled substance and recruiting a gang member.

Harry Storch, who was charged with conspiracy to commit grand theft by extortion and robbery, entered a guilty plea Wednesday to a charge of aggravated assault as part of a plea agreement with prosecutors.

Court records do not indicate if there is any agreement on length of sentence for any of the cases.

All 10 members of the gang who have entered guilty pleas are set for sentencing later this year in front of 4th District Judge Lynn Norton.

Boise police say they began investigating the “Slayer” gang last summer after getting a tip about a violent new group that liked to use guns and was becoming infamous for brazen robberies.

The Boise police gang unit began working with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives on the case. By April, the agencies searched two homes and the Ink Spot tattoo parlor in the Broadway Avenue neighborhood looking for guns and drugs.

Boise police officials say the BPD Swat Team and ATF teams served warrants at the tattoo shop and residences — one at 1402 Broadway Ave., one in the 1300 block of Longmont Avenue — around 5 a.m. April 3 as part of their investigation into the Slayer gang.

Officials say that officers seized guns, but they will not provide any more details.

Federal prosecutors say the ATF search warrant information — which would explain why police believed the Slayer gang had drugs and guns and what they actually found at those three addresses — remains sealed in federal files, even though that information was used to charge all 11 defendants.

By June, Ada County prosecutors charged 11 people in connection with the case with a variety of violent crimes, including robbery, extortion, recruiting gang members and aggravated assault.

When pleading guilty in August to charges of aggravated assault, recruiting a gang member and use of a deadly weapon in the commission of a crime, Jerry Brown told Norton he did “recruit new members for the Slayers and they do engage in criminal activities, your honor.”

Boise Police Sgt. Jeff Basterrechea, who supervises the department’s gang unit, said earlier this summer the Slayers “were one of the most organized gangs I’ve ever seen.”

“They had rank (leadership), a structure, a system of picking victims ... and they were committing robberies,” Basterrechea said. “And the more they did it, the more brazen they became.”

What remains unclear is who the victims of the Slayers were.

Because the case was taken to a grand jury, there are no probable cause documents to examine. Charging documents have names of victims, but do not say how those people were chosen.

The indictments do describe one particular attack on a man in November 2011.

According to court records, at least one suspected gang member, Devin Montgomery, met with a male victim “under the guise of purchasing a car” and then punched the victim in the head.

Two days later, prosecutors say two other gang members — Anthony “Kalani” Storch and Harry Storch — called the victim and demanded $50,000 in cash or they “would kill his friends, bosses, girlfriend, family.”

They told the victim to drop off the money at a local restaurant. Court documents say some of the Slayers discussed this mission with Jerry Brown.

Indictments also mention instances of gang members battering other people, selling marijuana and conspiring to commit crimes.