Body camera footage shows nine members of a U.S. Marshals Service task force falling to the ground as a second-story wooden deck they were standing on suddenly collapses.
Arrests were made in 10 cities, including Chicago.
The US Marshals Service, FBI and other law enforcement agencies are assisting in the search for the four men, according to the BOP.
The K-9 officer hurt in the shootout is no longer in the hospital, officials said.
The K-9 officer hurt in the shootout is still in ICU, officials said.