HOUSTON -- Four women have been arrested in connection with a patient wheelchair delivery scheme to defraud Medicare and Medicaid, KPRC Local 2 reported.

Texas Attorney General Greg Abbott said Terri Ann Thurman Orozco, Michelle Ann Ray, Sharon Johnson Thomas and Carmelita Lavette Thurman have been indicted on charges of conspiring to commit health fraud, money laundering and anti-kickback schemes with physicians.

Officials said the alleged scheme defrauded the companies of nearly $4 million.

Investigators said Orozco, Thurman and Ray own medical equipment companies that specialize in wheelchairs and scooters for Medicaid and Medicare patients. Thomas was a recruiter for all three companies, officials said.

The indictments allege that the companies conspired to obtain fraudulent paperwork from physicians who claimed the wheelchairs were medically necessary. The group allegedly used fake certificates to bill Medicare and Medicaid and supplied less expensive wheelchairs and scooters to the patients while pocketing the difference.

Officials said the group was involved in the scheme from August 2002 to December 2004.

The doctors that participated have already been convicted of health care fraud, officials said.