Attorney General Avichai Mendelblit has ordered an investigation into a news report suggesting that the judge assigned to Case 4,000 and the lead attorney investigating the case for the Israel Securities Authority coordinated legal proceedings.
The move follows a report by Channel 10 News on Sunday exposing a string of text messages between Tel Aviv Magistrates' Court Judge Ronit Poznanski-Katz and attorney Eran Shaham-Shavit.
Case 4,000, the latest involving Prime Minister Benjamin Netanyahu, centers on potentially illicit dealings and conflict of interest involving Israeli telecom corporation Bezeq and the Walla news website, which Bezeq owns. The police allege that Bezeq's controlling shareholder, Shaul Elovitch, ensured positive coverage of the Netanyahu family by Walla in exchange for the prime minister promoting government regulations worth hundreds of millions of dollars to the company. Elovitch, his wife and son and several senior Bezeq officials, as well as former Communications Ministry Director General Shlomo Filber and spokesman Nir Hefetz, two of Netanyahu's closest confidants, have all been arrested in the case.
One of the texts between the judge and the investigating attorney indicates that the arraignment hearings for the suspects were simply held "for the record," as Poznanski-Katz and Shaham-Shavit had already decided on their result.
In a WhatsApp chat obtained by Channel 10, Shaham-Shavit wrote to Poznanski-Katz that the prosecution was planning to seek the release of some of the suspects but not others.
"Try to act surprised," he wrote.
"I'm already practicing my surprised expression," she replied.

Following the report, Pozanski-Katz informed the president of the Tel Aviv Magistrates' Court, Judge Avichai Doron, that she was recusing herself from the case.
Doron has informed Supreme Court Chief Justice Esther Hayut that Poznanski-Katz will not conduct any hearings until the end of disciplinary proceedings against her, and said she was about to go on a sabbatical.
Case 4,000 has been assigned to Tel Aviv Magistrates' Court Judge Ala Masarwa, he said.
The Israel Securities Authority announced that Shaham-Shavit has been placed on leave until the matter is resolved.
"This is an unfortunate and regrettable event that we see as very serious," the Justice Ministry said in a statement.
"This incident goes against basic principles the prosecution and its officials are expected to follow. Following consultations with the head of the Securities Authority, the attorney general and the state attorney have ordered an investigation by the Civil Service Commission into these allegations."
Justice Minister Ayelet Shaked condemned the affair, saying that arraignment judges have the responsibility to rule strictly on the merits of each case.
She said that together with Hayut, she plans to ensure the Israeli judiciary's Ombudsman's Office investigates the issue.
Hayut sent a message to all judges on Monday saying, "On this morning, which is difficult for all of us, I would like to express my deep appreciation for your dedicated and hard work.
"I urge you to keep your spirits up. We will continue to do our work professionally and faithfully and will continue to do everything within our power to preserve the public's faith in the legal system, which numbers over 700 judges and senior officials who give their all to this job year-round."

Israel Securities Authority Director Anat Guetta has ordered an investigation into the matter as well.
"This is a serious issue and the ISA will conduct an urgent investigation into it. ISA investigators work day and night to protect the investing public and maintain the integrity of all proceedings. This case will be investigated and the ISA will act with full transparency," she said.
Attorney Jack Chen, who represents Shaul Elovitch, said he was appalled to learn of the alleged collusion. He said he expects his client to be released from police custody immediately.
The Israeli Bar Association described the report as "extremely disturbing" and said it "mandates a thorough investigation."
The Movement for Quality Government in Israel said it was "shocked by the text messages. If this is true, the judge and the investigator must be suspended immediately and disciplinary proceedings must be taken against them.
"The Movement for Quality Government places the highest importance on just and fair law enforcement. This conduct has dealt a significant blow to the Israeli legal system and has undermined the fight against corruption."
Meanwhile, the Israel Police announced on Sunday that Netanyahu would be questioned on Friday over Case 3,000.
The case centers on an alleged conflict of interest in the procurement of three German submarines in 2016. It does not implicate Netanyahu directly, but rather his attorney and cousin David Shimron.
A police official said investigators were likely to use this opportunity to question the prime minister in Case 4,000 as well.