Robbie Abell, owner of a Florida gun shop, says he alerted authorities that a suspicious man had come in asking about body armor. Five weeks later, Omar Mateen – equipped with weapons he bought at a different shop after Abell’s employees refused to sell to him – killed 49 people and injured as many at Pulse night club in Orlando.

UPDATE: Abell has since confirmed the agency he contact was the FBI.

The Wall Street Journal quotes Abell as telling them that his store, Lotus Gunworks of South Florida, “shut him down on all sales” after be began asking bizarre questions about body armor and bulk ammunition. “The questions he was asking were not the normal questions a normal person would be asking… He just seemed very odd,” Abell said. The armor Mateen asked about is not traditionally available to civilians.

Abell noted that he made a phone call during his time in the store, and appeared to be speaking in Arabic. Mateen is from an Afghan family, and his father – a prolific pro-Taliban Youtuber – is known to speak at least two Afghan languages, Dari and Pashto. Mateen’s wife, Noor Salman, identifies as “Palestinian,” which would make her a likely Arabic speaker. She has confessed to shopping for weapons with Mateen.

Abell says his store alerted authorities to the suspicious man, though he did not say which authorities– whether he spoke to local police, FBI, or Homeland Security. Local CBS 12 notes that Abell’s store appeared to be following the procedures “in line with the FBI’s push for people to ‘see something, say something,‘ if they witness anything that makes them feel uncomfortable.”

The FBI had been alerted to Mateen as a potential terrorist in the past. The FBI had investigated Mateen for violent remarks and suspect behavior three times between 2013-2014, while he was employed as armed security personnel at the firm G4S. He was never fired despite being investigated, however, and the FBI eventually dropped their probe against Mateen.

Witnesses speaking to media who knew Mateen throughout his life have consistently described him as odd, unsettling, and violent. Former classmates recall him threatening to kill everyone present at a cookout on one occasion because of the presence of pork meat; a former G4S coworker said he routinely discussed committing a massacre.

Before being killed by police on Sunday, Mateen left several Facebook messages pledging allegiance to the Islamic State, and also did so in a phone call to 911 from inside Pulse.