LOS ANGELES, CA – JULY 20: Parkland shooting survivor and activist David Hogg attends ‘Women’s March Los Angeles hosts March For Our Lives LA: Road to Change & the Parkland survivors & activists’ at St. Elmo’s Village on July 20, 2018 in Los Angeles, California. (Photo by Emma McIntyre/Getty Images)

FORT LAUDERDALE, Fla. (AP) — Authorities say a Florida man sent a threatening letter to the mother of a Parkland mass shooting survivor and gun-control activist.

News outlets report that 78-year-old Warren Bond was arrested Thursday. A federal grand jury indicted him earlier this month on a charge of mailing a threatening communication.

Authorities say Bond used the United States Postal Service last June to send the threatening letter to the mother of David Hogg, who attended Marjory Stoneman Douglas High School earlier this year when 17 people were fatally shot.

Hogg and several other students have since become national figures in the gun control debate.

Bond faces up to five years in a prison and a $250,000 fine. It wasn’t known if he had an attorney.