Rick Franklin, 27, is the only person Chicago police has charged after 75 people were shot during a single weekend

Three weeks after 75 people were shot in Chicago, making it the deadliest weekend of the year in the city, police have charged only one man - and are asking for the public's help in order to make more arrests.

Rick Franklin, a reputed gunman for the street gang Black Souls, was taken into custody on August 4, hours after police say he fired a shot at an intersection striking a 26-year-old man.

Franklin, 27, is charged with three felonies, including aggravated discharge of a firearm, being an armed habitual criminal and unlawful use of a weapon.

He was initially arrested for aggravated battery with a firearm but because the victim, who survived, would not cooperate with officers the charge was dropped, the Chicago Tribune reports.

During that first weekend in August, the Chicago Tribune reports that 75 people were shot - a dozen of them fatally.

Superintendent Eddie Johnson and Mayor Rahm Emanuel suggested that the public's lack of help has made it difficult for officers to make arrests.

‘We have to continue to get out in the community, engage them and know them better,’ Johnson told the outlet in an interview on Thursday. ‘We have to just be better at building relationships with people to make them more comfortable to talk to us.’

Police investigate a crime scene on August 5 in Chicago. The first weekend of August was declared the deadliest weekend of the year for the city

Twelve people were killed in Chicago during the first weekend of August. Pictured above is officers at a crime scene on August 5

According to the outlet, a tip or a statement from a witness did not help officers arrest Franklin. They were able to catch him by using a multi-million dollar system which detects gunfire and sends an alert to officers.

Police sad the system, called ShotSpotter, detected the shots Franklin fired on August 4 and sent an alert to the Harrison District's Strategic Decision Support Center.

Once officers at the center received the alert, they turned on the city's surveillance cameras near the intersection and caught images of the crime scene. According to the arrest report, officers saw someone getting into a blue Ford Focus and cameras tracked the vehicle until two officers spotted it and arrested Franklin.

While police have not charged anyone else in connection to the shootings from that weekend, authorities said they are making progress and have narrowed down suspects.

The city said it needs residents to come forward with information to help them solve more crimes. An officer is seen above walking by a crime scene in Chicago on August 5

Chicago mayor Rahm Emanuel (front) has deployed an extra 600 officers to patrol the streets of Chicago

A 27-year-old man was arrested on August 3 for a shooting in the South Side but has not yet been charged. Police said a 'concerned citizen' gave them a description of the shooter which led them to the 27-year-old.

A 26-year-old woman was also arrested on August 5 in connection to a shooting. Police said she drove the victim to the hospital and was seen on surveillance placing two handguns in a backpack. Authorities have not found the person responsible for that shooting.

In recent weeks, Emanuel has deployed an extra 600 police officers to patrol the streets as he faces mounting pressure to take action against the rampant violence or resign.

President Donald Trump has repeatedly spoken out about the violence in Chicago blaming the crime rate on Emanuel. In a statement earlier this month, Trump said community bonds with law enforcement need to be stronger.

'That's bad stuff happening. And probably, I guess, you have to take it from the leadership, it's called bad leadership,' he added. 'There's no reason in a million years that something like that should be happening in Chicago.'