In the hours after the shooting at a Donald Trump rally in Butler, Pennsylvania, the former president and presumptive Republican presidential nominee is gaining support from a former Obama ally.

Trump was wounded while speaking to supporters Saturday night. He was rushed off-stage by the Secret Service. The FBI has since identified the shooter as 20-year-old Thomas Matthew Crooks of Bethel Park, Pennsylvania, not far from the location of the rally. He was killed by federal agents. One rally attendee was killed, and another was critically injured, according to a Trump social media statement after the shooting.

Following the chaos, many, including Wall Street billionaire Bill Ackman, took to social media to express support for Trump. While Ackman did not mention the attempted assassination, he said this was a decision he had made “some time ago” after spending time with the former president.

“Today, when one announces an intention to support Trump, Biden supporters who know me tend to assume that I have lost it. I assure you that I have made this decision carefully, rationally, and by relying on as much empirical data as possible,” Ackman wrote.

He joins another prominent billionaire, Tesla CEO and X owner Elon Musk, who reportedly announced he would donate to Trump’s campaign prior to the assassination attempt.