A DaVita spokesman said the company suspects four patient deaths at its dialysis clinic in Lufkin to be caused by a former employee.

"We suspect an unusual cluster of four patient deaths in April," said Michael Chee in an interview Tuesday.

The cluster of patient deaths is not indicative of the number of patients who died in April, Chee said.

The company has said it fired an employee from its 700 South John Redditt Drive facility April 29, a day after closing its doors for an investigation into a recent spike in patient deaths by local, state and federal agencies.

A Lufkin police spokesman has said the department is investigating allegations made against one employee, which is a part of its ongoing investigation into the clinic.

Dr. David Van Wyck, a nephrologist who is vice president of clinical services for DaVita and working with state officials during the investigation of the Lufkin clinic, said on average two to three patients die a month at dialysis centers.

He said that they do not occur on a regular basis and patients on dialysis have a higher death rate than the general population. But in some ways, the doctor added, dialysis patient deaths tend to reflect the general population.

"What we noticed (at the Lufkin facility) was a pattern of deaths and health-related events and we think that those are attributable to the suspected actions of a single individual," he said.

DaVita and LPD would not release further information about the employee or investigation at the facility, saying the investigation is ongoing. No arrests have been made and no charges filed.

DaVita said it is currently working with state health officials to draft a corrective action plan in response to a report the state is expected to release in the coming weeks.

Chee refused to go into details about what kinds of corrective action the facility had been discussing with state officials before it can reopen.

"Anything we are dealing with the state right now, until it comes a matter of public record, is confidential and the state would say the same thing because we don't, again, know to what extent or what issues we will be working with them," Chee said.

Corrective action plans are requested by the state from dialysis centers after an investigation is conducted.

DaVita, which has been closed since April 28, cannot reopen without the state's approval. Chee said there is no indication from the state about when the facility would reopen, but he said staff will be ready to care for patients the day the center can reopen.

During the same interview Tuesday, Chee said a state surveyor's 2007 findings of inadequately trained personnel at the Lufkin dialysis center represent an "isolated incident" and not linked to a recent investigation by Texas Department of State Health Services, Lufkin Police Department and the Centers for Disease Control and Prevention. "We do not consider any of the events in that or prior survey findings related to the incidents that happened in the Lufkin facility this April," Chee said.

A survey conducted July 17, 2007, at the center stated a facility administrator changed several patients' dialysis treatments without consulting a physician.

"A review of the list of patients found 22 (out of 22) patients were being dialyzed with the incorrect dialysate," the report stated.

The surveyor stayed on site that day to make sure patients were returned to their doctor-ordered treatments and followed up Aug. 22 to see that the facility had followed through with its corrective plan, as approved by the state, said state spokeswoman Carrie Williams on Monday.

Surveys conducted in 2003 and 2006, at the facility's former location at 509 Chestnut Village, stated the facility was noncompliant with state health standards. The state also made follow-up visits to DaVita during those years to make sure the facility was carrying out its corrective plan, Williams said.

Staff writer Ashley Cook contributed to this report.