Transcript for US reeling amid rise in mass shootings
The nation is also reeling from the deadly rampage in Indiana. Part of an epidemic of mass shootings. Just overnight, three people killed and two injured in Kenosha, Wisconsin. And in Columbus, Ohio, one person was killed, five wounded, at a vigil for a murder victim. Tonight, we're learning more about the suspected shooter in Indianapolis. Police say he legally purchased the two assault rifles used in the attack after he had been interviewed by the FBI and had another gun seized. His own mother flagging him to authorities. Will Carr joins us from Indianapolis. Reporter: Tonight, a community is asking how a teenager, flagged as a risk, was legally able to buy two assault rifles, which authorities say he used to kill eight people at this FedEx. Just over a year ago, the FBI says it interviewed the suspected suspect after his mom alerted them, fearing he might turn violent. Police say they removed a shotgun from his house at the time and placed him on a temporary mental health hold. Indiana's red flag law bars anyone legally deemed dangerous from buying or owning a gun for at least six months. Four months after the FBI interview, authorities say the teen legally bought an assault rifle. He bought another later in the year. Authorities say he used both on Thursday. It's still unclear why the red flag law was not applied in his case. Last year, the police department felt that he was dangerous? A danger to himself, yes. Reporter: Did the system fail here? Only from the standpoint, if he would have been found in violation of that law, maybe he wouldn't have been able to purchase these weapons legally. But I don't know enough about it that I can say that anyone dropped the ball, per se. Reporter: Four victims were members of the local sikh community. How concerned are you finding out that the FBI interviewed him last year and even took a gun out of his house? It's very concerning. We need to hold our leaders accountable. We want answers and we want a full investigation. Will, what are you hearing from people on the ground there in that community that is now suffering its third mass shooting just this year? Reporter: Well, linsey, it's interesting. Flags are at half-staff across the city. But at the crime scene, we have not seen a single flower or a memorial. Like you would normally see at a mass shooting like this. Some people tell me they're simply numb to the violence. Linsey? Will, thank you. Now to the pandemic.
This transcript has been automatically generated and may not be 100% accurate.