The suspect behind a string of deadly shootings in Maine was turned away by a local firearms store three months before he opened fire.
Robert Card was refused a silencer for a firearm after he admitted that he was committed to a mental health facility, a local store owner said.
Card was found dead on Friday, ending a 48-hour manhunt.
The gunman had opened fire at a bar and a bowling alley on Wednesday in the city of Lewiston, killing 18.
More than a dozen people were also injured in the shooting.
Since then, details have emerged about Card, a 40-year-old army reservist with a history of mental illness and who had allegedly made violent threats in the past.
Maine firearms store owner Rick LaChapelle told The New York Times and ABC News that the suspect had entered his shop on 5 August to pick-up a silencer he had purchased online.
He then had to fill out a form, which included a question that asked: "Have you ever been committed to a mental institution?"
Card answered yes, Mr LaChapelle said.
The staff then looked at the form and informed Card that he was not eligible to purchase the silencer because of the answers he'd given on the questionnaire.
Mr LaChapelle said he believes the attacks would have been deadlier had the purchase gone through, because people would not have heard the gunfire.
"We did what we were supposed to do and hopefully saved a lot of lives by just following the proper procedures," he told the New York Times.