The family of 39-year-old Amy St. Pierre is speaking out about their profound loss.

"Our beloved Amy was brilliant, kind, big-hearted and simply the 'best of the best,'" her family said in a statement. "Loving wife and mother of two, middle sister to two brothers, and cherished daughter, she was truly our pride and joy."

St. Pierre worked at the Centers for Disease Control and Prevention's Division of Reproductive Health, according to CDC Director Dr. Rochelle Walensky.

"An Emory honors graduate and Georgia State MBA, Amy traveled the world with curiosity and courage," her family said. "She was driven by compassion, both in her work in the field of maternal mortality, and in her everyday life. Amy was selfless always, she wanted more for others but never for herself. Generous supporter of worthy causes, she was the social conscience of our family."

The Cobb County Department of Public Safety released 911 calls Thursday of suspected sightings of the shooting suspect prior to his apprehension in the county Wednesday evening.

"I just saw a man who fits the description walking through the woods of this townhouse area, um, with a hoodie on," one caller said.

Another caller reported seeing a man sitting outside under a tree while in their apartment building. "He's been sitting there, at this point, for maybe about 30 minutes. He has on like, a hoodie, and it's like the hood is, like, up over him, and he has a black book bag with him," the caller said.

In one call, a person reported a possible sighting of the suspect walking in front of their building. "I just got everybody out the office and came upstairs. So I don't know where he is right now," the caller said.

In another call, a person said they noticed "distinctly Air Force 1" shoe prints where they were walking, "which stood out to me because normally in this area that I walk is little muddy. I normally only ever see my shoe prints."

"The Northside Hospital family is grieving" in the wake of Wednesday's mass shooting in a waiting room at the Northside Medical Midtown office, Northside Hospital said in a statement on Thursday.

The hospital is encouraging people, wherever they are, to "take a moment or two" on Friday to "pause and reflect" in what the hospital is calling a "Day of Reflection."

"We deeply love and support the employees and patients who were directly involved, as well as others impacted in different ways," the hospital said. "Let us hope that this kind of tragedy never happens again -- not to us, not to anyone."

Hospital officials added, "We are incredibly grateful for the quick and courageous response of Atlanta-area law enforcement. Northside also thanks our colleagues at Grady Memorial Hospital for the care being provided to the victims. Their actions brought comfort and safety to our patients and staff at Northside Medical Midtown."

-ABC News' Will McDuffie

Three of the four women who were shot and injured remain in the intensive care unit, Dr. Robert Jansen, the chief medical officer at Grady Health, said at a news conference Thursday.

Two of those three women are "critical" and will return to the operating room for additional procedures, he said. The third patient in intensive care is stable and hopefully can move out of the ICU later in the day, he said.

The fourth woman who was shot is in stable condition, he said.

"As of right now everybody is as stable as they can be given the nature of their injuries," Jansen said.

Jansen said he's spoken with two of the injured victims.

"They have been traumatized," he said.

"They are very grateful for the support and care they've received," he said, however, "the fact that they were in a health care facility just makes it worse."

Jansen noted that "the impact" of this shooting "on the staff is something you can't imagine."

"Unfortunately, in this day and age, seeing shooting victims is almost a daily occurrence here," he said.

"But when they come in like this, particularly because it happened in a health care setting, it resonates more," he said, adding that the hospital staff is being offered support.