(CNN) -- The trial of an Air Force nurse charged with murdering three terminally ill patients by giving them fatal overdoses has been delayed by at least one day, an Air Force spokesman confirmed Monday.

Capt. Michael Fontana, a nurse at Wilford Hall Medical Center at Lackland Air Force Base in San Antonio, Texas, has also been charged with conduct unbecoming an officer for changing a medical document.

The trial, originally slated to start Monday, was delayed due to various court procedures and motions, said David Smith, the chief of public affairs operations for the Air Force's Air Education and Training Command.

The charges stem from an Air Force investigation into irregularities discovered in Fontana's administration of medications "which may have resulted in the death of an end-of-life patient," Smith told reporters earlier this year.

The nurse was charged with three counts of violating Article 118 of the Uniform Code of Military Justice. "It is considered murder," Smith said.

The three deaths occurred in July of 2008, Smith noted.

He said he did not know the motive but was confident no other patients were victimized.

"We know that there are no other patients involved in this case," he said.

Fontana, an intensive-care unit nurse who had worked at the hospital since 2006, the year he joined the Air Force, was released on his own recognizance and is continuing to work at the hospital, though he is no longer involved in patient care, Smith said.

"As far as we can tell, he has been an exemplary nurse," Smith said.

Fontana also served as a nurse at the Air Force Theater Hospital in Balad, Iraq, Smith said. His work there was investigated, "and there was nothing found," he said.

Wilford Hall Medical Center is the Air Force's largest medical facility.