The group is particularly known for two major conflicts with the Philadelphia Police Department. In 1978, a standoff resulted in the death of one police officer, injuries to several other people, and life sentences for nine members who were convicted of killing the officer.
In 1981 MOVE relocated to a row house at 6221 Osage Avenue in the Cobbs Creek area of West Philadelphia. Neighbors complained to the city for years about trash around their building, confrontations with neighbors, and that MOVE members were broadcasting sometimes obscene political messages by bullhorn. The bullhorn was broken and inoperable for the three weeks prior to the police bombing of the row house.
The police obtained arrest warrants in 1985 charging four MOVE occupants with crimes including parole violations, contempt of court, illegal possession of firearms, and making terrorist threats. Mayor Wilson Goode and police commissioner Gregore J. Sambor classified MOVE as a terrorist organization. Residents of the area were evacuated from the neighborhood. They were told that they would be able to return to their homes after a twenty-four hour period.
On Monday, May 13, 1985, nearly five hundred police officers, along with city manager Leo Brooks, arrived in force and attempted to clear the building and execute the arrest warrants. Water and electricity was shut off in order to force MOVE members out of the house. Commissioner Sambor read a long speech addressed to MOVE members that started with, "Attention MOVE... this is America". When the MOVE members did not respond, the police decided to forcefully remove the members from the house.
There was an armed standoff with police, who lobbed tear gas canisters at the building. The MOVE members fired at them and a gunfight with semi-automatic and automatic firearms ensued. Police went through over ten thousand rounds of ammunition before Commissioner Sambor ordered that the compound be bombed. From a Pennsylvania State Police helicopter, Philadelphia Police Department Lt. Frank Powell proceeded to drop two one-pound bombs (which the police referred to as "entry devices") made of FBI-supplied Tovex, a dynamite substitute, targeting a fortified, bunker-like cubicle on the roof of the house.
The resulting explosions ignited a fire from fuel for a gasoline-powered generator stored in the rooftop bunker. The fire spread and eventually destroyed approximately sixty-five nearby houses. Despite the earlier drenching of the building by firefighters, officials said they feared that MOVE would shoot at the firefighters.