Police in Ferguson, Missouri arrested about six protesters who gathered outside of the city's police station Wednesday night in wake of the upcoming grand jury decision that will decide whether or not to indict Officer Darren Wilson in the shooting death of Michael Brown.

A string of protests in the St. Louis suburb began over the summer after Wilson fatally shot the unarmed African-American teenager in Ferguson on Aug. 9. Several eye witnesses testify that the 18-year-old was shot execution style while he was surrendering with his hands in the air. However, the 28-year-old white cop claims that Brown was the aggressor and reached for his weapon.

A grand jury is expected to issue a ruling on whether to indict Wilson sometime this month, and as early as this week.

In the meantime, a group of protesters demanding justice for Brown held a demonstration at police headquarters in freezing temperatures on Wednesday, some chanting "Indict that cop," reports Reuters.

According to police spokesman Brian Schellman, 15 protesters gathered across the street from the Ferguson police department and eventually stood in the roadway, which impeded traffic. Shortly thereafter, other protesters joined in and shut down South Florissant Road. As a result, several protesters were arrested for blocking traffic while one was taken into custody on a police warrant, reports The Associated Press.

In preparation for the grand jury decision, Missouri Gov. Jay Nixon declared a state of emergency and asked for the National Guard to provide local police with backup.

Activists across the nation are also planning to hold rallies at federal courthouses regardless of the grand jury's decision.

Last week, Chief Tom Jackson announced that Wilson will be "immediately" returned to active duty if a grand jury decides not to indict him, reports Yahoo News.