The gunman who killed five people at a bank in Louisville, Kentucky, on Monday legally bought the weapon he used the week before, police have said.
He purchased the AR-15-style semi-automatic rifle on 4 April.
At a news conference, officials said two people - including a police officer - remain in intensive care.
Louisville Mayor Craig Greenberg called for a change in Kentucky law to prevent the weapon used in the attack being bought at a police auction in future.
Police confirmed that bodycam footage captured by first responders who attended the scene at Old National Bank in downtown Louisville will be released later.
A police officer who graduated into the force last month was struck in the head on Monday and remains in critical condition at Louisville hospital, officials said.
Four people have been released from hospital overnight, one other person remains stable in intensive care, while two others continue to be treated for non-life threatening injuries.
The victims have all been identified:
- Thomas Elliott, 63
- James Tutt, 64
- Joshua Barrick, 40
- Julianna Farmer, 45
- Deana Eckert, 57
The policeman who was struck in the head was identified as Louisville Metro officer Nickolas Wilt, 26.
Data compiled by the Gun Violence Archive shows that there have been at least 146 mass shootings - defined as those in which at least four people were shot - so far in 2023, including at least 15 since the start of April.
Mr Greenberg said 40 people in the city of about 628,000 have died from gun violence this year.
Jason Smith, chief medical officer at University of Louisville Health, who has led care for those injured, became emotional as he told reporters: "When you hear someone screaming mommy or daddy, it just becomes too hard to come in day in and day out and do that.
"Sooner or later it catches up to everybody."
The suspect was named as 25-year-old Connor Sturgeon, who police said used an AR-15-style semi-automatic rifle during the incident and was broadcasting the shooting online.
Sturgeon bought the gun from a local store, Louisville Metro Police Department interim chief Jacquelyn Gwinn-Villaroel told Tuesday's news conference.
The attacker was described by police and other officials as a current employee of Old National Bank.
Officials say he had no previous contact with law enforcement.
Kentucky is one of 26 states that allow most adults over 21 years old to purchase and carry a firearm without a licence.