LONDON -- Activists for victims of a deadly London high-rise fire have taken inspiration from an Academy Award-nominated film to press for more action by police. The signs read: "71 dead. And still no arrests? How Come?"

Three mobile billboards were driven through the British capital Thursday on behalf of the Justice 4 Grenfell campaign. The group was set up after fire ravaged the Grenfell Tower apartment block in June, killing 71 people.

In the film "Three Billboards Outside Ebbing, Missouri," a mother played by Frances McDormand uses large signs to berate police for failing to catch her daughter's killer.

Justice 4 Grenfell says it hopes the billboards will "keep this tragedy in the national conscience."

Get Breaking News Delivered to Your Inbox

Police say they are considering possible manslaughter charges in the blaze, but no one has yet been charged.

Huge investigations by police, fire officials and others are underway to determine how a blaze that started with a refrigerator in one apartment got out of control so quickly in the 24-story building.

Attention has focused the building's new aluminum cladding, installed during a recent renovation, and authorities want answers fast because thousands of other buildings in the country could be affected.

Angry residents want to know how building regulations that were meant to be among the world's best could have failed so catastrophically. Many accuse officials in Kensington and Chelsea, one of London's richest boroughs, of ignoring their safety concerns because the building was home to a largely immigrant and working-class population.