Four senior doctors at Kaplan Hospital in Rehovot and Hartzfeld Geriatric Hospital in Gedera suspected of illegally experimenting on humans were arrested Monday.

The national fraud squad has opened an investigation into the affair. The four are suspected of abuse, aggravated assault, causing death through negligence, fraud, forgery, breach of statutory duty, and disruption of legal proceedings.

The Tel Aviv Magistrate's Court on Monday extended by three days the remands of Kaplan-Hartzfeld deputy director Dr. Shmuel Levi and Dr. Nadia Kagensky. The third suspect, Dr. Alona Smirnov, was released to house arrest for five days, and the fourth suspect was released following an investigation.

Police searched the houses of all four suspects and confiscated incriminating documents.

Many of the details of the affair were revealed in a series of Haaretz articles on the subject, as well as Channel 2 TV's investigative documentary series "Fact."

In May 2005, the State Comptroller's Office slammed the hospitals over the illegal experimentation in a report.

According to a report issued by the investigations department of the Health Ministry and exposed by Haaretz, the hospitals in Gedera and Rehovot conducted illegal and unethical testing on thousands of elderly patients for years.

During one of the incidents described, twelve patients died either during the experiments or shortly after they took place, but these incidents were not reported to the Health Ministry or investigated, as is required by law.

The Health Ministry's director general filed a complaint with police following an internal inquiry into the affair and the fraud squad confiscated from the hospitals many documents pertaining to the experimentation.

The ministry's investigation revealed that some of the patients were included in the experiments without providing their consent, while some of them suffered from severe mental damage, which prevented them from being legally capable of providing consent.

According to the report, some of the tests did not even yield any medically or scientifically beneficial results. Furthermore, some of the experiments were conducted despite top doctors' warnings that they were illegal or unethical.

The report voices harsh criticism of the Helsinki committee at the hospitals, responsible for approving the experiments and failing to protect the public's best interests.

The ministry's report further condemns the hospital's management for failing to address the complaints and information handed to it over the past few years, describing the flawed medical procedures.

According to the report, some doctors received promotions, both in their professional and academic careers, on the basis of the illegal tests. In some cases, the tests were used as the basis for research studies published in local and international medical journals.

At least four doctors at the hospitals were named as experts in Geriatrics based on the illegal tests they allegedly conducted along with their colleagues.