She's a member of the Havasupai, a small Indian nation in northern Arizona with about 650 members. Most of the tribe lives in Supai, a picturesque village tucked away on the floor of the western Grand Canyon.
The call came from John Martin, a longtime anthropology professor at Arizona State University who had gained the tribe's trust, as much as any white person can.
The tribe had allowed Martin in its midst because members thought he could help them with their diabetes epidemic. After spending more than a year in Supai in the early 1960s, he published his doctoral dissertation on the tribe at the University of Chicago.
Tilousi says Martin told her that a student was about to defend another dissertation on a subject that would be of interest to her.
"John said that the guy had used our tribal blood in his research," she recalls. "I said, 'What?!'"
Her curiosity piqued, Tilousi attended the presentation at ASU. About 30 others also showed up, including Martin and Therese Markow -- a nationally known genetics-research professor, formerly of ASU, who had sponsored the doctoral candidate.
Tilousi listened intently as Daniel Garrigan discussed his work, which had included use of about 100 Havasupai blood samples: "He spoke about how the DNA of this isolated, intermarried group of people -- us -- was unique, and how my people had migrated to Arizona from Asia."
Non-tribal members might wonder what could be so offensive about a researcher explaining how Indians once had crossed the frozen Bering Straits into North America.
But to Tilousi and others in her tribe, that was like a scientist asking Christians from Nazareth to give blood for a diabetes study, then producing research to suggest that Jesus never existed. She was raised to believe that the retreat of waters from a global flood had carved the Grand Canyon, and that the Canyon is the birthplace of the human race.
"I knew we wouldn't have given this guy or anyone permission to do that study," says the 33-year-old Tilousi, one of few Havasupai to have earned a college degree. "I started to think, 'How dare this guy challenge our identity with our own blood, DNA.' Then I remembered when many of us gave blood years ago for a diabetes project. I wondered if this was the same blood."
She spoke up during the question-and-answer period: "I said, 'I'm from the Havasupai tribe, and I want to know if you asked us permission to do this study.' [Garrigan] was really nervous. He said no, not to his knowledge."
Tilousi recalls John Martin then saying something prophetic -- because a conflict of cultures was about to erupt:
"'The blood bath will start right now.'"
News of the ASU/Havasupai blood war reached the public last February, in the form of a lawsuit filed in Flagstaff's Coconino County Superior Court.
Tribal members sued shortly after completion of a comprehensive investigation by Phoenix lawyer Steve Hart, which ASU commissioned (with Havasupai approval) soon after Carletta Tilousi's outburst at the dissertation defense.
The suit names 75 Havasupai who may have been among those from whom ASU researchers collected more than 400 blood samples in the early 1990s. The defendants include John Martin, Teri Markow and the university itself.
Filed by attorneys Al Flores and Tilousi's husband, Robert Lyttle, it claims ASU researchers "went beyond all possible bounds of decency . . . so as to be atrocious and utterly intolerable in a civilized community."
Legal hyperbole aside, a New Times analysis confirms the tribe's allegations on crucial points, and raises questions about the complex intersection of modern science and the cultures of indigenous peoples.
Most unsettling is that the ASU researchers duped the Havasupai into giving blood under a pretext that the tribe's diabetes epidemic was their sole concern.
Instead, Teri Markow and others also used the blood to study tribal schizophrenia, inbreeding and migration patterns, without getting proper (or any) permission to do so.
"They challenged our identity and our origins with our own blood and without telling us what they were doing," says Carletta Tilousi. "We aren't just Indians griping about whatever. If this were someone else's blood being misused, I think it would hit home for them, too."
That said, all would have been fine if the Havasupai had approved the research projects.
Tribal members interviewed by New Times for the first time say they feel as if the researchers used them as unwitting guinea pigs, as human specimens.
As a chilling example, they point to an as-yet-undisputed piece of evidence first revealed in the Hart Report: