Updated

A marine biologist and television science commentator whose wife was brutally beaten in Washington last month says police have been investigating him in the attack and that he was for weeks denied visitation rights at the hospital.

David Guggenheim said in a message to family and friends that he returned April 7 from an out-of-town trip to find his wife, Svetlana, with a fractured skull, brain trauma and "incoherent" on the bedroom floor of their Washington apartment. He said police started focusing on him as a possible suspect even though he says he had proof that he was not in Washington at the time.

"What I didn't realize was that (the D.C. police department) would be blinded by their suspicion of me as the assailant and that they didn't take even minimal steps to verify my story in order to clear me as a suspect," Guggenheim wrote.

Police have not said why they would consider Guggenheim a suspect. Metropolitan Police Department spokeswoman Gwendolyn Crump declined comment Thursday because the investigation is ongoing. A grand jury is weighing the case.

Guggenheim, who posted his account on a blog last week, said two police detectives met him at the hospital April 19 and told him that he could not visit his wife until they received a statement from her. Guggenheim sued D.C. police May 7, saying they had barred visitors from seeing his wife in the hospital when she needed her family most. His wife has had surgery to remove blood and other fluids from her brain and to implant a tracheotomy tube and a feeding tube. She has a breathing tube and hasn't been able to speak.

Guggenheim, a senior fellow at the Ocean Foundation in Washington, has explored coral reefs in Cuba with CNN's Anderson Cooper and bills himself as the "Ocean Doctor." The couple has recently been experiencing financial difficulties, with bankruptcy filings showing them listing more than $400,000 in liabilities.

He declined to discuss the specifics of the case with The Associated Press over the last two days on advice of his lawyer, except to say that police had shown an "unhealthy interest in me" and that he had hired an attorney to defend against possible criminal charges. The lawyer, Aitan Goelman, declined comment Thursday.

He says the police responded to his court complaint by presenting a handwritten note from a nurse saying that his wife had "indicated her injuries were caused by her husband." He says he believes the document to be a fabrication, and Svetlana Guggenheim has told The Washington Post that she doesn't remember anything about the attack or about who assaulted her. Guggenheim said a nurse told him last Thursday that he could again visit his wife. He thinks that permission came because his wife signed a separate statement, videotaped by her daughter, indicating that Guggenheim had nothing to do with her injuries and that any statement to the contrary should be considered invalid.

His biography on the Ocean Foundation's website says he has led international marine conservation projects and is interested in sustainable fishing and brining ocean exploration and conservation programs to young students. He has appeared on "60 Minutes" and other programs to discuss marine research and conservation.