Kansas City, Mo. ? Imprisoned pharmacist Robert Courtney showed emotion just once as he described his scheme to dilute tens of thousands of prescriptions to boost profits.

When he recalled that he diluted a prescription used to treat a patient for metastatic renal cancer, Courtney put his hands to his face and wept, according to tapes of his interviews obtained by The Kansas City Star.

“I just liked (him),” said Courtney, who was sentenced five years ago to 30 years in prison in a drug-dilution scheme that potentially touched 400 doctors, 4,200 patients and 98,000 prescriptions.

Some of the medications were used to treat cancer and transplant patients and those suffering from HIV/AIDS.

Asked in the interview whether the renal cancer patient was a friend, Courtney dabbed his eyes with a handkerchief and replied, “Through the business.”

Courtney disclosed the details of his scheme to investigators, prosecutors and defense attorneys at a private jail in Leavenworth, Kan., after pleading guilty in February 2002 but before his sentence was imposed that December. The taped interviews, which lasted several days, offer the most complete glimpse of Courtney’s motive.

Because he pleaded guilty, Courtney never faced a trial. The only time he spoke in court was to offer two apologies.

During the interviews, Courtney says that the dilution scheme originated in early 1992 when he was drawing up some medication and noticed that there was more of the drug in the sealed capsule than the label indicated.

He said he was told the prescription included a 10 percent overfill to allow for spillage.

“That was the beginning,” Courtney says, pointing out that he quickly deduced that other drug ampules must have contained similar overfills.

He said he spared friends, family or acquaintances but few others before he was caught nine years later.

Courtney described his motivation at another point in the tape. “It was always profit-driven,” he said, adding, “which was really ridiculous because some drugs were very inexpensive.”

Courtney said he started out diluting the drugs by 10 percent but the amount had grown to 75 percent or more by the end.

Courtney’s scheme fell apart in 2001 when oncologist Verda Hunter called federal investigators. She became suspicious after a drug company representative pointed out that Courtney was selling more of a cancer drug than he was ordering from the pharmaceutical company.