Booker, who was at the lake with friends to watch a lunar eclipse, found himself pinned to the base of a tree and pummeled by men who also threatened to break his arms, he said.
He ended up with a minor concussion, cuts, bruises and had patches of his hair pulled out, according to reports.
“I don’t want to recount this, but I was almost the victim of an attempted lynching,” Booker wrote in his Facebook post. “I don’t want this to have happened to me or anyone. It hurts my soul, and my pride, but there are multiple witnesses and it can’t be hidden or avoided.”
After the assault, Booker called 911.
Booker said Monday that a few strangers who were white witnessed the attack and jumped in to help him escape.
“I’m here alive today because folks stopped being bystanders. They didn’t just film me,” Booker said Monday, adding that their help in the matter “affirmed that black lives matter.”
Law enforcement officials with the Indiana Department of Natural Resources said they are reviewing evidence and conducting interviews, but so far no arrests have been made.
Hundreds gathered Monday in front of the Bloomington courthouse to demand justice, where a speeding car plowed into at least one protester, according to a spokesman for the Monroe County Sheriff's Office.
Meanwhile, the local chapter of Black Lives Matter is calling for the tree incident to be investigated as a hate crime.
Indiana politicians also quickly condemned the attack on Booker.
“This violent show of racism is absolutely sickening,” former Democratic presidential candidate Pete Buttigieg wrote Monday on Twitter. “Something is deeply wrong in Indiana.”
Bloomington Mayor John Hamilton and City Clerk Nicole Bolden issued a joint statement Monday expressing “outrage and grief” over what they believed was a racially motivated attack.
Democratic state Sen. Mark Stoops said he was “horrified by the racist attack” and urged Republican Gov. Eric Holcomb to investigate the Department of Natural Resources officers for failing to make any arrests.
“This is not just an issue of violence,” Stoops said in a statement Monday, “this is clearly a hate crime and must be treated as such.”
Civil rights attorney Benjamin Crump called the incident “absolutely sickening” and an “attempted lynching.”
Capt. Jet Quillen of the Department of Natural Resources said the findings of the investigation would be forwarded to the Monroe County Prosecutor’s Office, and she would not comment further.
Katharine Liell, who is Booker’s lawyer, told WTTV that she is confident arrests will be made.
Prior to the attack, Booker said he apologized to the men after they told his group they were trespassing. Booker said the men started following his group as they tried to leave.
Then, he said, they “jumped me from behind” and made the others leave the area, according to reports.
The video shows one of the men holding Booker against the base of a tree on all fours. Voices off camera can be heard pleading with the men, “Stop! Let him go! Please let him go.”
Another scene shows an assailant yelling “nappy headed (expletive)” to someone off camera, and then adds "You invaded us!" and calls someone in Booker’s group a “stupid (expletive) liberal (expletive).”
“We were calm and polite, but looking back now, it’s apparent that these individuals began targeting our group the moment they saw myself, a Black man and were looking to provoke a conflict,” Booker wrote on Facebook.