Originally Published: 03 MAY 23 12:57 ET

Updated: 03 MAY 23 16:26 ET

By Rebekah Riess, Dakin Andone and Christina Maxouris, CNN

(CNN) -- Atlanta authorities are searching for the person who shot five people Wednesday at Northside Hospital Medical in Midtown Atlanta, killing one person and sending four others to the hospital, and then fleeing in a carjacked vehicle, Atlanta Police Chief Darin Schierbaum said Wednesday.

A 39-year-old woman died, Schierbaum said during a Wednesday afternoon news conference. The injured victims were also all women, ranging from 25 to 71 years old.

The suspect, whom authorities identified as 24-year-old Deion Patterson, left the building and is believed to have carjacked a vehicle nearby, the police chief said.

He is still at large and there are active leads in Cobb County and in the city of Atlanta, Schierbaum said. Officers in Cobb County were searching in the areas of Vinings, Cumberland and Truist Park, according to a Twitter post from the Cobb County Police Department.

"We are working diligently to bring this individual into custody," the police chief added.

The suspect is a former Coast Guardsman.

Patterson "entered the Coast Guard in July 2018 and last served as an Electrician's Mate Second Class," a statement from the Coast Guard said on Wednesday. "He was discharged from active duty in January 2023."

The Coast Guard said they are working "closely" with Atlanta police and other authorities in the investigation of the shooting.

"Our deepest sympathies are with the victims and their families," the statement said.

Multiple victims were undergoing surgery at Downtown's Grady Memorial Hospital -- Atlanta's only Level 1 trauma center. Their conditions were not immediately available.

Three of the patients are in critical condition, Dr. Robert Jansen, chief medical officer at Grady Health System, told reporters in an earlier news conference.

Police issued a "be on the lookout" for the suspect saying he should be considered armed and dangerous and should not be approached.

The Atlanta Police Department earlier released images showing the suspected shooter wearing a hoodie, asking anyone with information about his whereabouts to call 911.

A high-level source within the Atlanta Police Department told CNN the suspect and his mother arrived Wednesday for a medical appointment for himself. The man at some point became agitated and started shooting using a handgun. The suspect has a military background, the source said.

Atlanta Police spokesperson Chata Spikes similarly said the man was attending a medical appointment for himself when the shooting occurred. Police declined to further describe the nature of the appointment, citing HIPAA regulations.

The man's mother, who was uninjured, is currently cooperating with police, Atlanta Police told CNN.

Northside Hospital confirmed the shooting at its Midtown location, saying on Twitter it was cooperating with law enforcement.

"We urge people in the area to shelter in place and follow instructions from law enforcement on the scene," the hospital system said. "This tragedy is affecting all of us, and we ask for patience and prayers at this time."

US has seen 190 mass shootings in 2023

In what has become routine in America, Wednesday's shooting interrupted daily life in a place many would consider safe. This time, it was in a doctor's office, but so often it's been US schools, grocery stores and houses of worship.

Including the shooting at the Atlanta medical facility, there have been at least 190 mass shootings in the United States this year, according to the Gun Violence Archive, which, like CNN, defines a mass shooting as one in which four or more people are shot, excluding the shooter.

The Atlanta Police Department tweeted earlier Wednesday it was investigating an active shooter incident inside a building on West Peachtree Street, between 12th and 13th streets, saying multiple people had been injured.

Videos shared with CNN showed police running on the scene as sirens blared. Multiple fire trucks, at least one armored police vehicle and deputies from the Fulton County Sheriff's Office were seen outside the building, which sits in a bustling area of the city, with Google's offices, hotels, restaurants, apartment buildings and at least two day care centers located nearby.

Atlanta resident Annie Eaveson lives at the Atlantic House apartments a block away and told CNN her building was placed on lockdown as the incident unfolded.

I saw two people taken out on stretchers. Waves of armored officers went inside in shifts almost. You can see medical professionals huddled up in offices."

This is a developing story and will be updated.