SAN FRANCISCO, Dec. 7 (UPI) -- A popular San Francisco radio talk show host and former Catholic priest has been indicted on federal child pornography charges.

Bernie Ward, 56, was charged with three counts of distributing and receiving child pornography, Assistant Attorney General Alice S. Fisher of the Criminal Division said in a news release Friday.

Ward, a talk show host on San Francisco's KGO 810 NewsTalk, was arraigned Thursday in U.S. District Court for the Northern District of California.

Ward's attorney said the charges are based on incidents that occurred more than four years ago and were part of research for a book, The San Francisco Chronicle reported.

"As everybody knows, Bernie, for over 20 years, has been a progressive, opposed to insensitive authority -- he has been a champion of charities, non-profits for the homeless," Doron Weinberg said.

Weinberg said Ward was conducting research for a book "on hypocrisy in America" when he downloaded "a few images" of child pornography and "it came to the attention of the government in late 2004."

Ward faces a maximum of 20 years in prison on each count, a $250,000 fine, and a lifetime term of supervised release, the Justice Department said.