The defendant in a complex murder case involving a Mexican drug cartel, a West Contra Costa street gang and an Aryan Brotherhood drug dealer faces a new accusation: that he put out a hit on the attorney for a former cartel leader who agreed to testify against him.

Coby Phillips, 42, is a founding member of the Family Affiliated Irish Mafia, also known as FAIM, a street gang centered in the Rodeo/Crockett area that operates in California prisons as well. Phillips has faced serious criminal charges since the mid-2000s; he accepted a plea deal in a federal drug case, and was implicated in the murder of Aryan Brotherhood member Darryl Grockett, a former friend.

Phillips went on trial for Grockett’s murder in 2013, but the jury deadlocked and a mistrial was declared. While awaiting a second trial, authorities say Phillips made friends at the County Jail with a dangerous inmate named Jason Soletti, who was recently sentenced to life in prison, and has been linked to several in-custody stabbings where he used homemade weapons to attack other inmates.

By coincidence, Soletti was represented by the same defense attorney who negotiated a plea deal for Sergio Vega-Robles, a former Sinaloa Cartel associate who agreed to testify against Phillips. Vega-Robles was facing several felony drug-trafficking charges — along with the threat of deportation — but was allowed to stay in the United States as part of the plea deal.

Authorities found a cloth garrote in Soletti’s cell — and have found shanks in Phillips’ cell over the years — and say one of those weapons was to be used to kill Vega-Robles’ attorney during a client meeting between her and Soletti. But the hit never took place.

During a 2015 grand jury hearing, Vega-Robles’ attorney testified that she was warned by a prosecutor to stay away from County Jail.

Phillips’ attorney, Daniel Horowitz, called the new charges against his client a “Hail Mary” by prosecutors, whom he portrayed as desperate to keep Phillips locked up. Not only were Phillips and Soletti not friends, Phillips viewed Soletti as a threat, Horowitz said.

Soletti was claiming to be a member of the Aryan Brotherhood, which would have put him at odds with Phillips, Horowitz said, because of a conflict involving Phillips’ refusal to kill witnesses against Aryan Brotherhood members.

“(Phillips is) going to be placating this guy, making nice to him, and trying to keep him out of his way. Any allegation that they plotted against (Vega-Robles’ attorney) is absolutely ridiculous,” Horowitz said. He later added, “(Phillips and Vega-Robles’ attorney) don’t love each other; she represented somebody who theoretically lied a lot in order to not be deported and killed by drug cartels. She represented him. But that’s not really a motive to hurt somebody, and attorneys do that all the time.”

Authorities counter that they seized a jail note, allegedly written by Phillips, in which he says Soletti planned to kill the lawyer for him.

That letter surfaced after a jailhouse informant who testified that he had known Phillips for years came forward to police. In exchange for his testimony, he was freed from jail and relocated, court records show.

Horowitz denied that Phillips had written the note, saying “there is no evidence that’s his handwriting, and it isn’t.”

Prosecutor Tom Kensok countered Horowitz’s claim, saying, “I have a lot of writing of Phillips’ ” and cited testimony that the note came from him.

Phillips is expected to be tried in September. He will also face charges that he conspired to kill Grockett, who was found shot to death in October 2004 on Cummings Skyway in Crockett. No eyewitnesses to the killing have come forward, but police developed a murder case against Phillips and Jose Vega-Robles, convincing a number of former gang members to testify, including Sergio Vega-Robles, Jose Vega-Robles’ brother.

In a 2015 grand jury hearing, Sergio Vega-Robles testified that he, his brother and Phillips ran a drug-trafficking ring in the Bay Area during the mid-2000s, shipping methamphetamine from Mexico to Los Angeles, and then to the Bay Area. Sergio Vega-Robles said he set up safe houses in Benicia, Fairfield and throughout Contra Costa County, and paid a Richmond police officer for information on drug investigations.

Vega-Robles also testified that after Grockett’s killing, his brother confessed to him that he, Phillips and a third party — a cousin of the Vega-Robles brothers, who remains at large — shot Grockett and left him by his truck on Cummings Skyway.

Horowitz has denied these claims as well, saying that Phillips had no motive to kill Grockett, and that cellphone records show Grockett was alive after he and Phillips made a drug deal earlier that day. Two juries who viewed the evidence separately against Jose Vega-Robles and Phillips — in 2012 and 2013, respectively — found Vega-Robles guilty and deadlocked on Phillips.

Nate Gartrell covers crime, politics, and corruption in Contra Costa County. He joined the Bay Area News Group in 2014. Outside of journalism, he doesn't do much. He aspires to visit all 30 Major League Baseball stadiums. Reach him at 925-779-7174.