LAS VEGAS (AP) — A former aide at a Las Vegas outpatient clinic where authorities say patients became infected with hepatitis C in 2007 pleaded guilty Monday to felony neglect and other charges and agreed to testify against the former clinic owner.

Keith H. Mathahs, 76, could get probation or be sentenced to 28 months to six years in state prison under terms of the plea agreement, his lawyer and a prosecutor said.

Mathahs pleaded guilty to criminal neglect of patients resulting in death, criminal neglect of patients, insurance fraud, obtaining money under false pretenses, and conspiracy to commit racketeering.

“It’s been very difficult for my client and his family to go through this,” Mathahs’ attorney, Michael Cristalli, told The Associated Press. “The plea negotiations allow him a chance at probation. There’s an element of finality to putting an end to it.”

Clark County District Court Judge Valerie Adair postponed sentencing until after the trial of Dr. Dipak Desai and another former Endoscopy Center of Southern Nevada employee, nurse anesthetist Ronald Ernest Lakeman.

One former patient died early this year in the Philippines, and a second-degree murder charge was added against Desai, Mathahs and Lakeman. Each pleaded not guilty and remained free pending trial.

The judge on Monday dismissed the murder charge against Mathahs.

Desai, 63, and Lakeman, 65, face trial in April on 28 criminal charges also including criminal neglect of patients resulting in death, insurance fraud and racketeering. If convicted, they could face prison sentences far beyond the rest of their lives.

Prosecutors allege Desai, once a prominent former Las Vegas gastroenterologist and state medical board member, directed a penny-pinching scheme that included requiring staff at his Endoscopy Center of Southern Nevada and Desert Shadow Endoscopy Center to use left-over anesthesia in previously opened vials and to reuse colonoscopy scopes and bite plates from patient to patient.

Southern Nevada Health District officials in February 2008 notified more than 50,000 Desai patients to be tested for hepatitis and HIV. Authorities later determined that nine people contracted incurable hepatitis C, and said cases involving another 105 patients might have been related.

Prosecutor Michael Staudaher and Desai’s lawyer, Richard Wright, declined comment about Mathahs’ plea deal.

Lakeman’s attorney, Frederick Santacroce, said he has been talking with Staudaher about resolving the criminal case against Lakeman.

Wright lost a nearly two-year battle to show Desai is physically and mentally unfit for trial. Wright has also sought dismissal of 15 counts in the indictment, including a key racketeering charge and seven felony charges each of criminal patient neglect and disregard for patient safety.

Staudaher and prosecutor Pamela Weckerly contend that Desai is exaggerating the effects of heart ailments and strokes he suffered in 2007 and 2008 to avoid trial.

The hepatitis C outbreak spawned dozens of civil product liability lawsuits in state court against drug makers, and a federal fraud case alleging that Desai and his former chief clinic business executive overbilled health insurance companies.

Trial is pending in U.S. District Court in Las Vegas for Desai and former clinic business administrator Tonya Rushing in the federal criminal case. They have pleaded not guilty.

A Las Vegas private school headmaster who became infected with hepatitis C and his wife won a $500 million jury award in May 2010 against drug companies Teva Parenteral Medicines Inc. and Baxter Healthcare Corp. A separate jury awarded other plaintiffs $182.6 million in a case in which pharmaceutical distributor McKesson Corp. was also found liable. A third jury awarded $104 million in damages to plaintiffs.

In each case, plaintiffs lawyers alleged drug companies chose profits over patient safety by delivering large vials of the powerful anesthetic propofol to Desai clinics.

The clinics filed for Chapter 7 bankruptcy liquidation in July 2009, and Desai also filed bankruptcy.

Court-ordered talks yielded settlements in February in 41 other lawsuits involving drug companies. Israel-based Teva set aside about $285 million to pay its share of that bill.