Sneaking expensive equipment out of biology labs in the dead of night while working unsupervised graveyard shifts, two doctoral fellows managed to steal several years’ worth of lucrative medical research from Harvard Medical School (HMS) two years ago, according to charges filed earlier this month by federal prosecutors.

Jiangyu Zhu, 30, and Kayoko Kimbara, 32, who worked and lived together before their arrest, had been analyzing cells that could eliminate organ transplant rejection. The results of their research were “highly marketable scientific information,” according to FBI agent Scott Robbins’ affidavit.

Zhu illegally sold these discoveries to a Japanese biochemical company in late 1999 and 2000, the affadavit alleges.

The lab supervisor, Professor of Cell Biology Frank D. McKeon, tried to “keep tabs on the work being performed by Zhu and Kimbara, but this was difficult given their unusual hours and their reluctance to have meaningful discussions with him,” Robbins says in his affidavit.

Upon coming to work for Harvard, Zhu and Kimbara, Chinese and Japanese citizens, respectively, signed away to Harvard the rights to all discoveries they would make at the labs, a standard procedure.

But in 1999, they began doing research for their own purposes, federal prosecutors say.

According to the government, Zhu and Kimbara took materials from HMS worth over $300,000, much of which cannot be replaced. The Japanese company has returned all the materials it acquired, according to a statement issued by the U.S. Department of Justice.

Zhu and Kimbara face up to 25 years imprisonment and $750,000 in fines for conspiracy and theft of trade secrets.

The two researchers screened cells that could block calcineurin, an enzyme that makes organ transplants difficult by causing the immune system to reject the new organs.

Using information and technology developed by McKeon, Kimbara discovered two genes which successfully block calcineurin.

Immediately after the discovery, Kimbara and Zhu altered their work hours to an 11 p.m. to 9 a.m. shift in order to avoid McKeon’s supervision, the affadavit alleges.

Just before Christmas break in 1999, McKeon confronted the two on suspicions that they had made unreported advances, but Zhu and Kimbara denied everything.

In 1999, Zhu applied to run his own lab at the University of Texas. He got the job and hired Kimbara to work for him. They began work there in January 2000.

During Christmas break after the confrontation with McKeon, Zhu and Kimbara, working in the wee hours on the deserted campus, stole specialized biological packing crates from McKeon’s lab and shipped $5,000 worth of materials to Texas, the affadavit says.

The theft was discovered after Christmas break, and Harvard officials confronted Zhu and Kimbara, who denied everything and announced for the first time that they would be relocating to Texas, the affadavit says.

HMS has not changed its security policy since the incident, said spokesperson Danna Burtanger.

“Nothing similar has ever happened in recent memory,” she said.

—Staff writer Eugenia B. Schraa can be reached at schraa@fas.harvard.edu.