Police tape marks off the area where a shooting took place in downtown Dallas, Friday, July 8, 2016.
UPDATE 6:10 p.m.: WFAA is reporting the Dallas PD has initiated a "city-wide" roll call to verify the safety of every police officer in the city.
Dallas Police said on Saturday they had received a new anonymous threat against law enforcement across the city - two days after five officers were shot dead.
Officers crouched beside vehicles, armored SWAT team vehicles arrived and a helicopter hovered overhead.
Johnson was killed by a robot-delivered bomb - made up of C4 and "det cord" - after the shootings, which marked the deadliest day for United States law enforcement since the September 11, 2001, terrorist attacks. The department also said officers will be using a shotgun to break into a locked door inside the garage. "No suspect found", the police department tweeted.
Police asked news organizations to stop airing live video from the area as they carried out the search.
Patrick Zamarripa was a Dallas police officer who survived three tours in Iraq only to be gunned down at home. The agency said in a statement that 43-year-old officer Brent Thompson, a newlywed whose bride also works for the police force, was the first officer killed in the line of duty since the agency formed a police department in 1989.
CBSDFW.com, the website for the CBS affiliate in Dallas, reported a credible threat was made against Dallas Police on Saturday.
Police spokeswoman Sr. Cpl.
Other law enforcement departments around the country have been receiving threats, following police involved shootings of black men in Louisiana and MS, and the killing of five police officers by a sniper in Dallas.