Authorities in Florida are investigating a fire at the mosque that was attended by the Orlando nightclub shooter as a possible arson.
In an update on its official Facebook page, The St. Lucie County Sheriff's Office said surveillance video shows someone approaching the Islamic Centre of Fort Pierce around 12:30am on Monday, moments before a flash was seen and the fire started.
Firefighters extinguished the blaze and there was no word about how much damage the fire caused. No injuries have been reported.
The mosque was attended by Omar Mateen, who opened fire at the Pulse nightclub on June 12 in a rampage that left 49 victims dead and 53 wounded. It was the worst mass shooting in modern US history.
Earlier, Major David Thompson of the St. Lucie County Sheriff's Office declined to speculate on whether the Sunday anniversary of the September 11 terrorist attacks played a role in the fire.
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 is 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 steal 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.