Advocates for a Missouri man imprisoned for nearly 25 years for a murder he claims he didn't commit are stepping up their efforts to free him, starting with petitions urging the state attorney general to stop blocking a new trial. Lamar Johnson has been imprisoned since 1995 in the fatal shooting of 25-year-old Marcus L. Boyd. St. Louis Circuit Attorney Kim Gardner, in collaboration with the Midwest Innocence Project, has issued a report saying police pressured the only eyewitness in the case. The witness later recanted. Johnson appealed Hogan’s ruling and a hearing is scheduled for Wednesday before the Missouri Court of Appeals.