"While we don't yet know the motive of the shooter, he targeted a facility known to be heavily populated by Sikh employees", said the coalition's executive director Satjeet Kaur.
Family members gathered at a nearby hotel to await word on loved ones - and some employees were bused there for tearful reunions. FedEx released a statement early Friday saying it is cooperating with authorities and working to get more information.
Indianapolis police provided an update on the investigation into the shooting Friday morning.
Paul Keenan, the special agent in charge of the FBI's Indianapolis field office, said on Friday that agents questioned Hole past year after his mother called police to say that her son might commit "suicide by cop".
Mr Jawandha said that his father had brought his mother food and was getting ready to go inside when the shooting started.
Eight people were killed.
Thursday's gun violence at the FedEx centre was the second mass shooting in recent weeks targeting workplaces employing a high concentration of people of Asian descent. McCartt said the slayings took place in a matter of minutes. They have been identified by the Marion County Coroner's Office and IMPD.
The families' agonizing waiting was exacerbated by the fact that most employees aren't allowed to carry cellphones inside the FedEx building, making contact with them hard.
"When you see notifications on your phone, but you're not getting a text back from your kid and you're not getting information and you still don't know where they are ... what are you supposed to do?"
McCartt said during a Friday afternoon news conference that they had responded to Hole's home past year after reports of a man voicing suicidal ideas, which he repeated to responding officers.
At 11:30 a.m., Carson said she had just heard from her daughter, Jessica, who works in the facility.
The Indianapolis carnage follows a spate of mass shootings across the United States in recent weeks, including at an office building in southern California, a grocery store in Boulder, Colorado and at several spas in Atlanta, Georgia where eight people, including six women of Asian descent, were killed.
Thursday's rampage was the third mass shooting in Indianapolis this year. Five people, including a pregnant woman, were shot and killed in January, and a man was accused of killing three adults and a child before abducting his daughter during at argument at a home in March. "Our Consulate (in Chicago)@IndiainChicago is in touch with the Mayor and local authorities in Indianapolis as well as the community leaders", he said in a tweet.
US President Joe Biden called the mass shooting incident as "national embarrassment".
"It stains our character and pierces the very soul of our nation", Mr Biden said.
He said police have not yet uncovered a motive for Thursday's shooting but added that law enforcement officers seized a gun from him past year. "We're still trying to ascertain the exact reason and cause for this incident", she said.
Another FedEx employee, Levi Miller, told NBC's "Today Show" he ducked out of sight when he saw a hooded figure holding what appeared to be an AR-style semiautomatic rifle who shouted and opened fire outside the facility. "Luckily, I was far enough away to where he (the shooter) didn't see me".
Gov. Eric Holcomb ordered flags to be flown at half-staff until April 20, and he and others decried the shooting, with some noting how frequent such attacks are.
Indianapolis Metropolitan Police Department spokesperson Genae Cook said that when officers arrived at the FedEx facility, they found an "active shooter incident".
Another man who told media he was a witness said his niece was sitting in her vehicle in the driver's seat when the gunfire erupted, and she was wounded.