The Ontario Provincial Police and Hamilton police said charges against James Kopp have been dropped, but didn't say why, the Hamilton Spectator reported.
He was the sole suspect in the 1995 wounding of Dr. Hugh Short when a rifle bullet came through a window of his home in Ancaster.
The police statement said Kopp remains a "person of interest" in several other abortion doctor shootings in Canada and the United States.
Kopp is serving a life sentence plus 10 years for the 1998 fatal shooting of an Amherst, N.Y., doctor who ran an abortion clinic. He was sentenced by a New York federal court in 2007, and he appealed his sentence earlier this year, the Toronto Star reported. On April 6, a three-judge panel unanimously upheld his conviction and denied his appeal, the report said.