Jane Hawking says she'd been worried for years about her ex-husband, the celebrated Cambridge physicist Stephen Hawking. She'd heard reports from his nurses and her children—and had seen injuries with her own eyes—that suggested Stephen, who is almost completely paralyzed as a result of the degenerative disease amyotrophic lateral sclerosis (ALS), was being mistreated. Police investigated Hawking's injuries after he was hospitalized in 2000 with a broken wrist and facial gashes, but he refused to talk to them.

Jane's worries, however, intensified last August after one of Stephen's nurses called their daughter Lucy, 33, to report that the scientist had been burned after he was left out in the blistering sun in his garden. A nurse alerted police, who launched an investigation. Since then, Stephen's caregivers have been quoted in the press blaming his second wife, Elaine, 53, for causing his mysterious injuries. One former paid caregiver, who left in June over what she describes as a "safety issue," told PEOPLE she "witnessed forms of abuse...and found it completely unbearable in that household. [Elaine] calls him 'thicko' to his face. He would tell us, 'I cannot be left alone with her.' Those were the very words that he typed on his computer."

Police are looking into allegations of assault and have so far interviewed 10 of the scientist's current and former nurses. Elaine refuses to comment, but Stephen, 62, author of 1988's A Brief History of Time, issued a strong denial from the Cambridge hospital where he has been recovering from pneumonia since December. "I firmly and wholeheartedly reject the allegations," he said. "My wife and I love each other very much, and it is only because of her that I am alive today."

Stephen and Jane married in 1965 and had three children. In the 1970s Jane befriended a local choirmaster, Jonathan Hellyer Jones, and eventually they began having an affair. Stephen left Jane in 1990 after falling for his nurse Elaine, whose husband had designed the voice box that enables him to speak. Both couples divorced, and Stephen and Elaine wed in 1995.

Gregory Benford, 63, a physics professor at the University of California, Irvine, and friend of Stephen's, says Hawking, who has round-the-clock care, "is a remarkable, self-propelled character. I would really doubt anyone could put anything over on Stephen Hawking." Even so, Jane, who married Hellyer Jones in 1997 but kept Hawking's name, says she was "almightily relieved" to hear of the investigation. "At last," she says, "somebody is taking this situation seriously."