Last September when Sidney Jaffe, a former land developer in Florida , was jogging near his luxury mid-town apartment in Toronto, two men abducted him and whisked him across the border to Buffalo.

They put Jaffe on a chartered Lear jet to Orlando, Fla., to face 28 charges of unlawful land sales practices. Jaffe, 57, had been captured by the bounty hunters hired to track him after he had defaulted on his $137,500 bond in May, 1981.

Last week in Orlando a federal judge dismissed Jaffe's complaint that his constitutional rights to privacy and due process were violated when the bounty hunters abducted him in Canada and returned him to Florida. Jaffe sought $100 million in damages against Accredited Surety and Casualty Co. of Orlando, the bail bonding company that hired the bounty hunters.

U.S. District Judge John Reed said Jaffe's U.S. constitutional rights do not extend across the border. But he gave Jaffe's lawyers 20 days to find whether there is any way Jaffe's Canadian abduction can be subject to American law.

The whole issue has raised a mini-diplomatic war between the two governments, who share an extradition treaty.

Incensed Canadian authorities are seeking the extradition of the two bounty hunters, Timm Johnsen, 40, of Orlando and Don Kear, 33, of Fairfax, Va.

"We're looking at every possible legal and diplomatic option," Charles Cole, director of Canada's External Affairs Department legal division told reporters. He said the case raises serious issues for further Canadian-U.S. relations.

Jaffe was an American citizen until last year. The bounty hunters testified they did not know he had already declared his Canadian citizenship when they abducted him.

While there are plenty of questions about how Jaffe beame such a diplomatic cause ce'le bre, there is little doubt of the complexity of the legal questions surrounding his case.

As one of Jaffe's prosecutors put it, "This is no usual case."

In the mid-1970s Jaffe's company, Continental Southeast Land Corp., purchased a cow pasture in Putnam County in northern Florida and named it St. John's River. They sold one-acre and half-acre lots, primarily by mail, to about 1,100 purchasers mainly from out-of-state. Another 500 individuals, primarily Florida residents, also invested in the development, according to prosecutors.

The lots were purchased under an "agreement for deed," a contract to buy the property. When completing their payments, purchasers were promised in printed brochures a warranty deed that would guarantee their clear title.

"Most of them wound up with nothing or a quitclaim deed," said Stephen Boyles, the state's attorney who prosecuted Jaffe. A quitclaim is a deed to to property or right to the property but without a guarantee or warranty to the title.

Later these investors discovered tax liens, mortgages and several contractor's liens on the property, Boyles said. After receiving complaints, his office began an investigation under the new Florida Uniform Land Sales Act.

The prior encumbrances on the land amounted to about $2.5 million, according to Boyles. Jaffe was ordered by the Florida Land Sales Board to stop issuing quitclaim deeds. His corporation went bankrupt. The state charged him with 28 counts of land sales fraud.

Jaffe complained that he was being prosecuted as an example under the tough new law. When he was due in court for trial last May, he did not appear.

The bail bonding company hired the bounty hunters to find Jaffe, who had cost them $137,500.

Under Florida law and common law, a bail bondsman has the right to arrest and return a fugitive. The issue here is whether these rights extend across international borders.

The accounts of Jaffe's abduction differ widely.

Jaffe testified in federal court that after jogging in Toronto on Sept. 23, he returned to his condominium where two men were waiting for him in the lobby. He said they identified themselves as Ontario police and he agreed to go with them.

But then, Jaffe said, they beat him, handcuffed him, threatened to kill his daughter, hit him on the back of the head with a pipe and threatened to kill him at the border if he balked.

One of the abductors was Johnsen, who calls himself a "skip-tracer." He's been tracing fugitives who "skip" for 20 years all over the world.

Johnsen testified that Jaffe tried to jump out of the car window and that he was handcuffed for his own safety. Johnsen said Jaffe offered them bribes, including the equivalent of the bonding fee. Johnsen insisted that at no time did the bounty hunters use force.

Johnsen testified that when border officials asked the occupants of the car if they were U.S. citizens, everyone, including Jaffe, said yes. Johnsen also testified that he immediately contacted the FBI after returning Jaffe to the U.S. An FBI agent took the stand and vouched for Johnsen's statement.

Back in Florida, Jaffe received a five-year sentence for failing to appear for his original trial. He was convicted in a subsequent trial for land sales fraud and received a 35-year sentence. He is serving time in a medium security prison in central Florida.

Prior to sentencing, prosecutor Boyles was asked by the State Department to delay sentencing because of complaints about the kidnapping from the Canadian Embassy.

"I didn't," said Boyles in a soft drawl, "because there were no grounds . . . most of it was poppycock."

Neither Jaffe's attorneys nor attorneys for the bail bonding company would comment.