Adrián Lamo, a hacker best known for breaking into the computer networks of The New York Times and other major corporations, and for reporting the Army whistle-blower Chelsea Manning to the authorities, was found dead on Wednesday in Wichita, Kan. He was 37.

Mr. Lamo’s body was discovered in an apartment in the city, The Wichita Eagle reported. His father announced the death in a post on Facebook on Friday. Kate Flavin, a spokeswoman for Sedgwick County, Kan., said on Saturday that the cause of death was unknown.

Mr. Lamo was 22 when federal prosecutors accused him of breaking into The Times’s computer network, creating fake usernames and running up over $300,000 in data research fees. Mr. Lamo also gained access to the computer networks of Yahoo, Microsoft and Cingular Wireless, prosecutors said.

“It’s like someone kicking in your front door while you’re on vacation and running up a $300,000 bill on your phone, and then telling you when you arrive home that he had performed a useful service by demonstrating that your deadbolt wasn’t secure enough,” James B. Comey, then the United States attorney in Manhattan, said in 2003, referring to Mr. Lamo’s activities.