On February 16, 1970 a nail bomb placed on a window ledge of the Park Police substation in the Upper Haight neighborhood of San Francisco exploded at 10:45 p.m. The blast killed police Sergeant Brian McDonnell. Law enforcement suspected the Weather Underground but was unable to prove conclusively that the organization was involved.[64] A second officer, Robert Fogarty, was partially blinded by the bomb’s shrapnel. Secret federal grand juries were convened in 2001 and again in 2009 to re-open the Park Precinct cold case in an attempt to again tie WUO members Billy Ayers, Bernadine Dohrn, Howie Machtinger and others to the deadly bombing.[65] Ultimately, it was concluded that members of the Black Liberation Army, whom WUO members affiliated with while underground, were responsible for not only this action but also the bombing of another police precinct in San Francisco as well as bombing the Catholic Church funeral services of the police officer killed in the Park Precinct bombing in the early summer of 1970.