Authorities say they've recovered a terrorist poisoning manual from the laptop of a Long Island man accused of killing his wife by dosing her coffee with a potassium cyanide.

David Steeves pleaded not guilty to upgraded murder charges on Monday in Suffolk County Court following the death last month of his estranged wife, Maureen. He was initially arrested on attempted murder charges.

Suffolk Assistant District Attorney Janet Albertson said investigators found an electronic copy of "The Mujahideen (moo-jah-he-DEEN') Poisons Handbook" on the man's computer. The prosecutor also noted that after his arrest, Steeves gave authorities a seven-page written confession.

Defense attorney Joseph Hanshe says his client is innocent and the confession was coerced. Steeves is being held without bail.