A military veteran’s microphone was cut off during a Memorial Day event in Ohio, as he was explaining the role that Black Americans have in the holiday’s history.

Retired Army Lt. Col. Barnard Kemter was in the middle of his speech at a cemetery in his hometown of Hudson, Ohio when the event’s organizers muted his mic. A video of his speech shows that the 77-year-old started tapping it a few times before asking for help. He then kept speaking, telling the Washington Post that he instead used his “Army command voice.”

“I assumed it was a technical glitch,” he added. His speech starts at the 47:40 minute mark in the video above and is cut at 50:40, when he started discussing how freed Black slaves were some of the first people to honor those who died in the Civil War, after the Confederacy surrendered in 1865.

Event organizer Cindy Suchan—who invited Kemter to be the keynote speaker—told the Akron Beacon Journal that the audio was intentionally lowered because his remarks were “not relevant to our program for the day,” which was “honoring Hudson veterans.” His volume was turned up after two minutes.

Suchan said organizers told Kemter “to modify his speech and he chose not to do that.” She said the mic was muted even though a sound engineer refused to do so. The engineer later told Kemter that the mic wasn’t malfunctioning, but that he was purposely muted.

Kemter believes the organizers were “censoring” him, according to the Post. “I find it interesting that [the American Legion] … would take it upon themselves to censor my speech and deny me my First Amendment right to [freedom of] speech,” Kemter told the Beacon Journal. He went on to opine that “this is not the same country I fought for.”

“Throughout history, there has been a lot of claims about who actually performed the first Memorial Day service,” Kemter told the Post. “With this speech, I chose to educate people as to the origin of Memorial Day and why we were celebrating it.” Kemter was trained as a combat medic and served in the Amy from 1965 to 1995. “A lot of people viewed this as a healing speech and paying a tribute to the African Americans that started Memorial Day,” he said.

The Ohio American Legion said it is investigating the incident.