It has been 17 months since Jack B. Palmer first made a quiet complaint through internal channels at Infosys, the giant Indian outsourcing company he works for, saying he suspected some managers were committing visa fraud. Since then, Mr. Palmer says, he has been harassed by superiors and co-workers, sidelined with no work assignment, shut out of the company’s computers, denied bonuses and hounded by death threats.

But what has driven him nearly crazy, with bouts of depression alternating with rage, Mr. Palmer said, is the silence. Since last April, Mr. Palmer has been stewing day after day in his home near Montgomery, Ala., contemplating a blank Infosys screen on his computer and agonizing over whether his whistle-blowing was worth it.

“They did the worst thing they could do to someone who is used to working 80 hours a week,” Mr. Palmer said. “They sit me at home and cut me off from everything. My life is floating in Infosys purgatory.”

Mr. Palmer’s experience since he filed his first report in October 2010 alleging misuse of business visitor visas for Indian workers is a cautionary tale about the perils of confronting a big corporation. Mr. Palmer’s travails have been compounded because he is in a small minority of Americans employed by the huge company, which has $6.8 billion in annual revenues and about 15,000 employees in the United States alone, most from India.