LUFKIN - The investigation continues at the DaVita Dialysis Center in Lufkin after allegations of criminal activity by an employee.

The husband of a patient that died last month at that clinic told us Tuesday -- that an emergency room doctor said a Heparin overdose was the reason his wife died after she got sick.

"I got proof," Walter Metcalf said. "It's in the hospital records."

But according to DaVita officials -- it's not possible that a dialysis technician gave the drug without first seeing what is called "the charge nurse."

"If it was a medicine," said a DeVita employee, while showing our crew where supplies are stored. "They'd have to let the charge nurse know."

But, in a state report conducted last year -- it says "two clinic employees told a state surveyor they were administering treatments against a physician's order, under the order of a supervisor."

And another thing: Mr. Metcalf claimed that once he got the diagnosis of his wife's condition - he gave the doctor's report to DeVita.

"The doctor said that she had been overdosed with Heparin," he said. "(I took the findings over to DaVita) and handed it to someone. They said 'we'll take care of it and see that she doesn't get overdosed again. Well, she did."

DaVita officials were asked about Heparin and declined to comment, citing privacy laws.

After his wife died on April 1st, Metcalf demanded answers about the safety of the dialysis center.

He says, not one phone call was returned.

"I really think they'll push it down to the lowest level instead of taking responsibility at the top where it belongs," he said.

DaVita disagrees, saying - the facility is safe.

"This has been a safe facility," said DaVita spokesman Michael Chee. "It will always be, and we're very anxious to get back to providing care the minute we're ready to open our doors."

The death of Metcalf's wife -- is just just one of many cases that prompted Lufkin Police to conduct their own investigation.

"It's a big process when you start counting all the employees, patients and patients families," Lt. David Young said. "It's been extensive, with a large number of people being interviewed."

And what about Metcalf's allegations of under-staffing?

The state report claims that was a problem in the past.

Last july, the Texas Department of Health and Human services said the DaVita facility was not properly staffed

But once again -- DaVita says staffing was never an issue -- and that the report was stated wrong.

"We are required by state law and also to keep the license to keep the facility open, to maintain minimum number of staffing by state law and we never fell below what was required.," said Chee.

DaVita stands by its statement that the recent deaths at the facility -- came at the hands of one employee, who has been fired.

But the state will have the final say -- when a report is issued in the next few weeks.