First, investigators contacted the couple’s clients — all maintained they had never heard of them.

Next, investigators talked to physicians who supposedly worked on Medicaid bills for the couple’s home health care companies but they, too, had never heard of the Amoses.

These discoveries were among the clearest signs to prosecutors that Oluyemisi Amos, 35, and her husband Felix Amos, 66, would represent the latest scam in a string of Houston health care fraud cases.

The couple pled not guilty in Houston federal court Thursday following an indictment for multiple counts of health care fraud totaling more than $24 million.

“Mr. Amos has every confidence in the American legal system and is confident he will be exonerated of these charges,” said attorney Charley Davidson.

Oluyemisi Amos’ attorney, Philip Hilder, said his client looks forward to “resolving this matter by having her day in court.”

The Houston-area couple are suspected of falsely billing Medicare through their numerous home health companies, Acting United States Attorney Abe Martinez said in a statement. They are charged with conspiracy to commit health care fraud, health care fraud and money laundering.

The Amoses submitted their first fraudulent claims to Medicare in 2011, after purchasing the Houston-based home health company Advanced Holistic Healthcare Services Inc., according to the indictment. After a year of ownership, the married couple billed Medicare for two years of Advanced Holistic services, eight months of which would have been prior to their purchase of the company.

Medicare then paid Advanced Holistic approximately $2,156,800.

The Amoses said a local doctor certified this bill, but investigators determined this physician did not refer or certify patients for Advanced Holistic’s services. He said had never even heard of the company.

The Amoses established a pattern of this fraud over the next four years, according to the indictment.

In 2014, Oluyemisi purchased the home health company Access Practical Solutions, Inc., but this time identified herself as the sole owner. She designated Medicare payments for APS to be deposited in her personal bank account, which totaled approximately $7,308,530 for a four-month period of alleged services.

Later that same year, Oluyemisi became the registered agent and president of GetUpAndWalk, Inc. and transferred all Medicare funds from that account — $4,500,000 — into either her or her husband’s bank accounts.

The Amoses last suspected scheme took place in 2015, when Oluyemisi became the registered agent and director for Guarranty Home Health Agency, Inc. Medicare paid this company approximately $2,740,000.

The couple allegedly falsified claims for at-home health services for beneficiaries that never received any services.

These beneficiaries were also not ordered to receive services by any of the physicians the Amoses named in their claims, according to court documents.

All the patients and physicians listed in the Amos’ Medicare claims denied ever having heard of their home health companies.

Investigators consider Houston a major hub of Medicare fraud, where nearly 200 Houston area residents have been indicted on health care fraud charges since 2009 — 136 convicted of fraudulently billing for nearly $650 million.

The Houston-based Medicare Fraud Strike Force — a team of investigators from the FBI, IRS, U.S. Department of Justice, local U.S. Attorney’s Office, U.S. Department of Health and Human Services’ Office of Inspector General and Texas Attorney General’s Office — were responsible for exposing the 2005-2012 Riverside General Hospital $158 million psychiatric scam, one of many others discovered in the Houston area.

In that case, the former president of Riverside, the operator of one of Riverside’s satellite locations and a group home owner were each convicted of conspiracy to commit health care fraud and conspiracy to pay kickbacks after the submission of fraudulent claims for partial hospitalization program services to Medicare through the hospital.

Just last month, the owner of Elite P. Care Medical Services, Verona Spicer, 47, was sentenced to 33 months in federal prison for her part in a $1 million Medicare and Medicaid scam. Earlier this year, physician Faiz Ahmed, 64, was convicted in federal court for his part in a $13 million Medicare plot.