Gladwyn Taft Russ III was serving as a pallbearer at the Saturday service and was loading his father's casket into a hearse when the undercover deputies approached him.
Relatives said two deputies dressed in coats and ties grabbed Russ and kneed him in his back before using a Taser on him. One deputy's gun fell out of its holster.
"Everybody was so scared. We thought it was a drug deal gone bad," said Ronnie Simmons, another pallbearer and Russ' brother-in-law. "We almost dropped the casket."
New Hanover County Sheriff Sid Causey told The Star-News of Wilmington that five of the officers involved would be disciplined, although he wouldn't say what punishment they would face.
"I apologize to anyone that was there," Causey said. "Family, friends, relatives. ... That was a bad decision."
Russ, 42, had failed to surrender after being charged with threatening his ex-wife, who lives in another state. After his father died on Nov. 11, Russ agreed to surrender to authorities after the funeral.
When deputies approached Russ, he "went wild" and spat on the officers, Chief Deputy Ed McMahon said.
Russ was charged with assault on a government official, resisting an officer, disorderly conduct and felony malicious conduct by a prisoner. A call to Russ's home went unanswered Wednesday night and it was not yet known if he had retained an attorney.