Instead of sending a message to those who died in Rancho Tehama Reserve, California, he appeared to have copied and pasted a message meant for the 25 victims of the Sutherland Springs, Texas, attack, which happened on November 5. "The FBI and Law Enforcement has arrived", Mr Trump tweeted shortly after 8.30pm on Tuesday evening.
The tragic shooting in Sutherland Springs, Texas has changed our way of thinking.
Some Twitter users suggested that Trump may have just been confused by all the mass shootings in America lately.
A gunman opened fire on a local elementary school in rural Rancho Tehama near Sacramento in California killing at least four people, on Wednesday. "Awful insult to the victims of both", the European media director of Human Rights Watch said.
The time that the shooting at Sutherland Springs, Texas took place, president Trump was with his wife Melania Trump at the five-nation, 12-day tour of Asia.
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Everything you want to do is coming with a pure heart and a pure intention". "Well, you never know". To the latest, the protesters have broken into the theater and destroyed the assets there.
Twitter users questioned the timing of the tweet and wondered if Trump accidentally sent out a saved draft.
Rancho Tehama is about 190 miles north of San Francisco.
Matt McDermott tweeted, "The President of the United States is tweeting at midnight about the wrong mass shooting and it's like the 500th most insane Trump story of the week".
"The shooter literally took his vehicle and rammed their fence and gate, entered the grounds on foot with a semiautomatic rifle", he told USA media.