Merritt L. Sharp III has a strained relationship with police, which keep detaining him either at gun point or in handcuffs, because of his son, Merritt L. Sharp IV.

An appellate court concluded last month that the Orange County Sheriff’s Department isn’t immune from a civil lawsuit following a 2013 incident in which they held Sharp III for more than 20 minutes because he protested that he wasn’t his son, who is 22 years younger and who they wanted for suspicion of burglary.

Sharp III, now 77, who lives in San Clemente, is suing for unspecified damages.

It’s his second trip to court for the same kind of mixup.

In 1997, Garden Grove police neglected to bring a warrant when they stormed Sharp III’s auto-body garage. At the time, they were looking for his son, then a parolee. Police detained Sharp III at gunpoint for 45 minutes, prompting a lawsuit that eventually led to a $1 million jury award.

In the 2013 incident, sheriff’s deputies did bring an arrest warrant when they arrived at the Sharp residence in San Clemente. But that warrant was for Sharp IV, and when they held Sharp III handcuffed in the back seat of a police cruiser even after they’d sorted out the confusion, they may have violated his constitutional rights, his attorney said.

“(Police) just do what they want to do and then make up everything (to justify it),” said Sharp III’s attorney, Jerry Steering.

The Orange County Sheriff’s Department declined comment on the ongoing litigation.

In the 2013 incident, deputies saw a man run from the back door of the San Clemente house. After failing to catch him, they noticed Merritt Sharp III, then 73, walking out on his front porch. Deputies arrested Sharp III at gunpoint and forced him to the ground, injuring his rotator cuff, according to Steering.

Sharp III then was handcuffed and placed in the backseat of a patrol car, while he protested that they were after his son, not him. Deputies held him in handcuffs in the backseat for an extra 20 minutes after sorting out the mix-up because he argued too much, according to the lawsuit.

Deputy Ryan Anderson told Sharp III, “If you weren’t being so argumentative, I’d probably just put you on the curb,” the suit alleges.

At the time they wanted Sharp IV — who has a history of violent crime — for felony burglary.

A divided panel of justices with the Ninth Circuit Court of Appeal ruled that the deputies lost their qualified immunity after they retaliated against Sharp III for arguing. Up until then, justices said, the deputies were covered by qualified immunity against any lawsuits even though they had repeatedly violated Sharp III’s constitutional rights.

Once deputies realized they had the wrong person, they had to release him and not hold him for being argumentative, justices said.

Steering described the ruling as “precedent-setting.”

“This is a giant case and a step against the erosion of the Fourth Amendment,” Steering said, referring to the right against illegal search and seizure.

It’s unclear if the second incident will generate a windfall for Sharp III. Following the 1997 incident, a judge lowered the $1 million jury award to $50,000.