SAN JOSE – A former South Bay bank executive convicted of securities fraud is facing new charges he submitted six improperly altered or entirely fabricated letters of support to the court to obtain a lighter sentence, according the U.S. Attorney’s Office.

Mounir Gad, 35, of Los Gatos, is charged with document tampering, identity theft and criminal contempt.

Earlier this year, Gad, who served as vice president of Santa Clara-based Silicon Valley Bank, pleaded guilty to two counts of securities fraud. Federal prosecutors said he shared non-public information with a friend who allegedly used it to execute securities transactions.

According to a criminal complaint filed Nov. 19, Gad submitted a dozen letters of support to the court in advance of his sentencing for the securities fraud counts, the U.S. Attorney’s Office said in a news release Tuesday. Three of the letters allegedly were altered without the authors’ knowledge, adding language that praised Gad’s good character, and three allegedly were not written by the purported authors.

On Nov. 3, before the alleged document tampering and identity theft crimes came to light, U.S. District Court Judge Lucy H. Koh sentenced Gad to two years of probation, a $500 fine and a $200 assessment for each of the securities fraud counts. He could have received up to 20 years in prison and a $5 million fine for each count.

The author of one of the allegedly altered letters attended Gad’s sentencing hearing and heard the court reference statements she had not written and were not true, according to the complaint. She contacted Gad’s defense attorney, who in turn notified the court.

According to the complaint, the court held another hearing on Nov. 10, at which Koh said, “What I considered and what I found to be very compelling about this letter, are lies that Mr. Gad put in the letter.”

Gad faces up to 20 years in prison and a $250,000 fine for the document tampering count and up to five years in prison and a $250,000 fine for the identity theft count, prosecutors said. There is no maximum statutory penalty for criminal contempt.

Gad made his initial court appearance on the new charges Tuesday. Magistrate Judge Kandis Westmore scheduled his next appearance for Nov. 26 for detention and identification of counsel. He is also set to appear Dec. 8 for further proceedings related to the securities fraud charges.