He licked the self-addressed envelope, sent it back and waited to hear if he would get any money.
In truth, there was no lawsuit - but there was DNA.
The letter was part of ruse devised by detectives to get a sample of Athan's DNA and connect him to a slaying that had gone unsolved for nearly 21 years.
Less than two months after the letter came back to the Seattle police, saliva on the flap of the envelope was matched genetically to semen taken from the body of 13-year-old Kristen Sumstad, who was raped and strangled in 1982.
Athan, 35, was arrested on murder charges May 21 at a construction site in New Jersey, not far from his home in Palisades Park.
"Money is the curse of all evil," Detective Richard Gagnon said. "And this guy - we said, `There's a form, sign it."'
Athan was 14 at the time of the slaying. He was seen pushing a hand truck and a large brown box down a street in the city's Magnolia neighborhood the night before Kristen's body was found in a television box behind a store about four blocks away.
When questioned, he told investigators he had used the hand truck to steal firewood from his neighbors.
He remained on a list of suspects, but there was not enough evidence to prosecute him.
Ten years later, scientists at the Washington State Patrol crime laboratory tried and failed to extract a DNA profile from the sperm. By last year, however, DNA technology had advanced enough that a second attempt succeeded.
Gagnon and his partner, Detective Gregg Mixsell, ran the results through state and federal crime databases but did not find a match.
They needed a sample of Athan's DNA. But with some 300 "cold cases" on file, Gagnon and Mixsell had to work on a shoestring budget.
"I can't say, `Hey, chief. Give me a week to follow this guy around and see if he spits out a cigarette,"' Gagnon said.
A colleague suggested the bogus lawsuit, and another detective drafted the letter.
"I get the letter and I thought it was real at first," Gagnon said. "I thought, `Jeez, this is a great idea. What do we have to lose? Let's send it."'
Police mailed the letter in mid-February and got it back a few weeks later. On April 23, Beverly Himick, a forensic scientist at the crime lab's DNA division, passed on the good news to Gagnon and his partner.
"They have put so much work in these cases," Himick said. "They have so many cases and they're just two people. To help them solve this case is so rewarding."
Athan's attorney, John Muenster, said he will try to get the evidence thrown out. "My opinion is that evidence was illegally seized," he said.
Investigators and prosecutors expect that effort to fail.
"Police ingenuity and police creativity does not equate to police misconduct," said Tim Bradshaw, the prosecutor on the case. "Police ruses have been well recognized and well accepted and shown to be constitutionally sound for some time."
Around the country, countless people wanted on criminal charges have been caught after being sent letters inviting them to come to a certain place to collect unclaimed tax money or win cars, trips, cash, football tickets, even sneakers.
Police have also been known to put suspects under surveillance in hopes they might discard a cigarette or a wad of gum from which DNA could be drawn. In Florida in 1998, spitting on the street led to the arrest of a rape suspect.
Professor John M. Junker, who teaches criminal procedure at the University of Washington School of Law, likened the phony-letter trick to the use of undercover officers: "The courts have said you have no expectation of privacy when you are sharing information willingly with someone who turns out to be an undercover agent."
By Elizabeth M. Gillespie