AMHERST — Employee timecard fraud and misuse of campus resources at the Physical Plant at the University of Massachusetts have escalated to the theft of an estimated $77,000 and involve at least nine employees, according to university officials.

As the internal investigation begun in 2015 continues, the findings are being turned over to the state attorney general’s office for additional review.

UMass spokesman Edward Blaguszewski this week released details updating the status of the investigation. The value of the time and materials at the center of the investigation, roughly $50,000 in February 2016, has now risen by more than 50 percent.

The internal investigation into the Environmental Services Unit prompted six employees to leave the university, while three other employees have been put on temporary suspension for their alleged roles in the thefts.

“Significant allegations were brought to our attention, and we moved quickly to investigate and take action,” Andrew Mangels, vice chancellor of administration and finance, said in a statement released by the university. “UMass is the steward of public dollars and we take that responsibility very seriously.”

The Physical Plant has an annual budget of $42 million and nearly 600 employees.

A spokeswoman for the attorney general’s office would not confirm or deny whether the matter was referred for review.

In a matter that Blaguszewski said is unrelated, another employee at the Physical Plant was recently placed on administrative leave. That person has not been identified and no details have been released about the reasons for that employment action.

As a result of the review into the timecard incident, several measures were put in place last year to improve accountability. They include pre-approval of overtime in advance by an assistant director of Physical Plant; increased tracking and accountability of time and attendance through the timecard system; upgrades and improved management review and approval of time submissions; improved accountability and management of materials at on-campus supply locations; and more stringent oversight to prevent the use of employee labor for non-university projects.