The California man accused of kidnapping and raping Jaycee Dugard has issued an apology in a jailhouse letter in which he talks about "a sexual problem believed to be impossible."

Phillip Garrido sent a letter of apology to a Sacramento TV station Thursday. Phillip Garrido sent a letter of apology to a Sacramento TV station Thursday. (Rich Pedroncelli/Associated Press)

In a letter received by a Sacramento TV station on Thursday, Phillip Garrido says he wants to "apologize to every human being for what has taken place."

Garrido and his wife, Nancy, are charged with abducting Dugard when she was 11 years old from a South Lake Tahoe bus stop in 1991. They allegedly held her captive for 18 years in their backyard. Both have pleaded not guilty.

Garrido's lawyer, Susan Gellman, said her client is expressing genuine remorse. She also said there are "obvious issues" over whether he's mentally competent to stand trial.

In a previous letter to the TV station, Garrido alleged Dugard's civil rights were being violated during questioning with authorities.