A Jewish man who died following protests wasn't afraid to make his voice heard.

Paul Kessler, 69, was a "staunch Democrat" with a "sharp mind" who "loved a good argument," according to Kyle Jorrey, former editor of the Thousand Oaks Acorn. He was also one of the "longest-running active letter writers" for the newspaper.

THOUSAND OAKS, Calif. Paul Kessler attended many demonstrations associated with progressive ideals, his friend reported on Tuesday.

And some of his final moments were spent among pro-Israeli and pro-Palestinian demonstrators amid the conflict between Israel and Hamas in Thousand Oaks, a suburb northwest of Los Angeles.

The 69-year-old Kessler became embroiled in a dispute during simultaneous protests on Sunday, Ventura County Sheriff James Fryhoff said. He died a day later from injuries sustained after falling and hitting his head on the ground during a confrontation between two factions. Kessler, who was Jewish, was part of the pro-Israeli group.

"My husband left the house with an Israeli flag and never came back," said his wife, Cheryl Moshe Brisky, a Chabad rabbi in Agoura Hills.

Rabbi Moshe Brisky in his office. Rabbi Moshe Brisky in his office. Tyler Kingkade / NBC News Brisky said he reached out to Kessler's wife after learning the couple had attended services at his synagogue. The family requested privacy and plans to hold a private funeral after realizing that thousands of people would want to attend, Brisky told NBC News on Tuesday. He said hundreds of people have offered to help cover funeral expenses.

Like other incidents that have occurred across the country since the start of the conflict, Brisky, who had just returned from Israel visiting families of hostages held by Hamas, said Kessler's death brought the conflict home.

"When you see a 69-year-old man on a street corner with an Israeli flag, and you find out that two minutes after this picture was taken, he was pushed to the ground, hit his head, and he's no longer alive, it wakes us up to realize that there are consequences, that there is real hatred in the streets," he said.

Still, Brisky said Jews should not hide their identity.

Fryhoff said at a news conference on Tuesday that witnesses on both sides of the demonstrations have conflicting accounts of what led to Kessler's fall. He urged anyone with information or video footage of the protests to come forward and cautioned people not to spread false information.

Investigators have identified the suspect, whom authorities described as a 50-year-old man, but Fryhoff said no arrests have been made. The suspect remained at the scene and was one of several 911 callers who requested medical assistance for Kessler, the sheriff told reporters.

The sheriff, who did not specify what detectives were looking for during the search, said detectives obtained a search warrant for the suspect and his home in Moorpark on Monday. He was detained and released more than an hour later after traffic had stopped in Simi Valley.

Kessler's death is being investigated as a homicide, Fryhoff said.

Kyle Jorrey, former editor of the Thousand Oaks Acorn, remembered Kessler as a "staunch Democrat" with a "sharp mind" who "loved a good argument."

"He was a very engaged (liberal) political person, and he wasn't afraid to let people know how he felt," Jorrey said. "It doesn't surprise me at all that he would be counter-protesting at his age."