Jakarta. The Jakarta Police raided an illegal abortion clinic in Central Jakarta and found fetal remains disposed in a septic tank, a police spokesman said on Tuesday.

Three suspects were arrested for running the illegal clinic at a rented home on Jalan Paseban Raya, Senen, with police saying they had been convicted of the same crime before.

Officers used several sacks to retrieve what were believed to be fetal remains from the septic tank for forensic laboratory tests.

"According to the suspects, the aborted fetuses were disposed into septic tank after being crushed using a certain chemical substance. We are still investigating the type of the chemical used by the suspects," Jakarta Police spokesman Yusri Yunus told reporters at the police headquarters.

According to their accounts, fetuses of up to two months old are easier to crush with the chemical, but sometimes they had to deal with ones older than four months, the officer said.

"During Friday's raid, we found a fetus that was about six months old and already had hair," Yusri said.

The suspects are identified by their initials: M.M., a doctor, R.M., a nurse, and S.I., who handled administration works at the clinic.

Investigation showed the clinic had been operating for 21 months, during which it received 1,613 patients and 903 of them had an abortion.

Police said the suspects earned Rp 5.4 billion ($395,000) in profit from the illegal clinic. They charged Rp 1 million to abort fetuses of up to one month old and the tariff went up for older fetuses.

To abort fetuses above three months old, the cost could go up to Rp 15 million, Yusri said.

Police expanded their investigation to look into the alleged involvement of at least 50 nurse-midwives in the network.

"Initial investigation showed 50 nurse-midwives might have been hired to seek patients, while the abortion took place in this clinic," he said.

"There are other clinics like this one, but after the raid they closed their operations and hid," Yusri said.

Police couldn't immediately question witnesses in the case because the identities of the patients were concealed.

"There is a problem because the patients' personal data are incomplete, but we will trace them through bank accounts used in their transactions," Yusri said.

Police alleged most of the patients came to the clinic to abort extra-marital pregnancies.