The sister of the gunman from the attack in Dayton, Ohio, is among nine people that were killed in the Sunday incident, police said on Sunday.
Megan Betts, 22, was confirmed to be among the dead at a news conference in which the victims’ identities were revealed.
At least 27 people were also left injured in the mass shooting, which occurred barely 24 hours after another shooting incident in El Paso that left some 20 people dead, and less than a week after a gunman opened fire at a garlic festival in California, killing three people including two children.
Police shot dead the gunman in Sunday’s incident within a minute of him opening fire.
The latest incidents come at a time when fresh calls for tighter gun control laws have emerged.
New Jersey Senator Cory Booker has expressed his support for the calls to avail stricter gun laws, saying the U.S. seems to be “accepting the idea that these [shootings] are going to be a regular occurrence”.
The two incidents prompted orders from President Donald Trump to have U.S. flags flown at half-mast.
“God bless the people of El Paso Texas. God bless the people of Dayton, Ohio,” President Trump said.
