An overnight fire at a Fort Pierce, Florida, mosque that was attended by the gunman in the deadly Orlando nightclub shooting was intentionally set, police said Monday morning.
In an update on its official Facebook page, St. Lucie County Maj. David Thompson said investigators collected evidence showing a person set fire to the Islamic Center of Fort Pierce on purpose.
"Video tape captured an individual approach the east side of the building," Thompson said. "Immediately after the individual approached, a flash occurred and the individual fled the area."
The surveillance footage was later released by the sheriff's office.
Thompson said the center was unoccupied. He added that the sheriff's office is investigating the incident as an arson.
The center was where Omar Mateen once worshiped while living in the area. Mateen killed 49 people and injured 53 at the Orlando gay club in the early morning hours of June 12. It was the worst mass shooting in modern U.S. history. Mateen was later killed in a shootout with police.
According to NBC affiliate WPTV-TV, crews responded to fire at the Islamic Center shortly after 12:30 a.m. after 911 calls that the building was on fire. The blaze was quickly extinguished and no one was hurt. The extent of the damage was unclear.
"It is with a very heavy heart that we have to announce that last night around midnight, there was an arson attack on our Mosque," the Islamic center wrote on their Facebook page. "Please keep us in your Du'as and prayers."
Thompson declined to speculate on whether the Sunday anniversary of the Sept. 11, 2001, terrorist attacks played a role in the fire but said given the circumstances it could be a hate crime.
Multiple agencies, including the State Fire Marshal's Office, the federal Bureau of Alcohol, Tobacco, Firearms and Explosives and the FBI, are investigating. Sheriff's officials said they will be releasing the video and asking for the public's help in identifying the person responsible for the fire.
It's not the first time the mosque has seen trouble since the Orlando attack.
A few weeks after the nightclub shooting, a man was beaten outside the mosque, according to Sheriff Ken J. Mascara. Early on July 2, deputies were called by a man who said someone was trying to burglarize a vehicle. Arriving deputies found a man bleeding from the mouth who told them he was approached by someone who "asked him what he was doing and then punched him several times in the face and head."
The man was stopped by deputies and arrested a short time later.
The Council on American-Islamic Relations said in a statement that a man in a truck had stopped outside the mosque earlier that day and made slurs, including, "you Muslims need to get back to your country."
Mateen's father is among the roughly 100 members that attend the mosque.
Monday marks the beginning of the Muslim holiday of Eid al-Adha.