In a grassy cemetery in Westfield, N.J., a tiny handwritten note appeared on the morning of June 2 next to the plain gray headstone for Helen List and her three children. It read: "Now you can rest in peace." Next to it was a bouquet of flowers and another message, this one scribbled on yellow note paper: " . . . John's been caught. June 1, 1989." On that date, a man whom police believe to be John Emil List, 63, Helen List's husband, was arrested in Richmond, 17 1/2 years after he allegedly killed his entire family, including his mother, then laid their bodies on top of sleeping bags in the living room of their decaying 19-room Westfield mansion and slipped into obscurity. The man arrested in Richmond is named Robert P. Clark, 57, husband of Delores Clark, and an accountant described by police and acquaintances as a hard-working churchgoer of modest means who lived quietly in the Denver area for more than 15 years before moving to Virginia in February 1988. "He was just an average-type person," said Patrick Ferguson, a neighbor of Clark's in the planned community of Brandermill, 15 miles southwest of Richmond. "He went to work in the morning, came home at night. If things needed {to be} done around the house, he did them. You want to write about your next-door neighbor, you write about Bob." Since his arrest, much has been written about Clark, who waived extradition this week to New Jersey, where he faces five counts of first-degree murder. Authorities say Clark, now in jail in Elizabeth, N.J., has denied being John List and signed his extradition papers as Robert Clark. A worldwide police hunt for List began after "America's Most Wanted," a nationally broadcast television program, aired a segment May 21 in which a plaster bust of what List might look like today was shown. The broadcast prompted more than 200 calls from viewers. The one that led authorities to Clark was brief. "It was, 'The person you're looking for is at this address,' " and then the caller hung up, FBI spokesman Wilber E. Garrett said. On June 1, agents interviewed Delores Clark at the couple's three-bedroom, ranch-style house, then went to the Richmond accounting firm where her husband had worked for 16 months and arrested him. "He was kind of unemotional about the whole thing," Garrett said. Clark denies that he is List, but Garrett said Clark's fingerprints match those on a gun permit application that List filled out a month before the slayings. He said Clark also has two scars that match scars List has: one behind his right ear, the other on his abdomen. Although Clark has refused requests for interviews, his former secretary, Sandra Silbermann, said he had called her from the Henrico County (Va.) Jail "to apologize for all the commotion . . . . He called when he knew all the bosses would be out, to say he felt sorry this had happened." Silbermann, like others who know Clark, described him as unfailingly polite and neatly dressed. He was a conscientious employee, she said, a modest man of modest means who drove a 1981 Ford Escort and brought his lunch in a brown bag. "I was really hard-hit when this happened," Silbermann said. "I felt like a close friend had died. "I felt I couldn't trust my instincts." Friends and relatives recall List, who had been an insurance salesman and accountant, as a quiet man devoted to his church. Searching for a motive as to why he might kill his wife, mother and children, police found that List was under financial and other pressures. The family's Victorian house was heavily mortgaged, and List reportedly was upset by his wife's chronic health problems and his children's behavior, authorities said. "If he was having problems, why didn't he just pack up and walk away from it?" Helen List's sister, B. Jean Syfert, asked a reporter for the Richmond Times-Dispatch. After the Nov. 9, 1971, slayings, List reportedly wrote letters to Syfert -- "He said there was no other way out" -- and his minister, and then turned down the thermostat, turned on the lights and canceled newspaper delivery in an effort to delay discovery of the bodies, police said. The victims -- Alma List, 85; Helen List, 45; and the couple's three children, Patricia, 16; John Jr., 15; and Frederick, 13 -- were not found until nearly a month later. The last trace of John List was his 1963 Chevrolet Impala, which was found at John F. Kennedy International Airport in New York City three days after the bodies were found. Authorities believe List headed west and started a new life. In late 1972, Robert Clark was living in a trailer park on the outskirts of Golden, a suburb west of Denver, according to Robert Wetmore, a self-described drifter who said he met Clark when both were working evenings at a nearby hotel. Gary Morrison said he met Clark at the same hotel in late 1973 or mid-1974, and still considers him his best friend. Morrison said Clark "had an obsession with history . . . . You could ask him, 'Who was the king of England in 1312,' and he would tell you not only who was king, but who his sons and daughters were . . . . It had to be very difficult for him to bury his own history." A chef, Morrison said he worked with Clark in the kitchen of the hotel. "He could handle anything that came along without going off the deep end or reacting negatively," said Morrison, adding that when he accepted a job in 1975 at a country club in Parker, Colo., he took Clark with him. Wetmore said he helped Clark move from the trailer park to a one-bedroom apartment in the early 1970s. Clark later moved to a two-bedroom apartment, Wetmore said, because he needed more space to play war games, which involve setting up miniature armies on big plywood sheets. Morrison said that by 1977, Clark had begun to find work as an accountant, List's occupation before he disappeared. That same year, Clark went to a church social where he met Delores Miller, whom he would marry in 1985, according to a neighbor. When Clark moved in September 1978 into a five-building complex in east Aurora, another Denver suburb, he listed Miller as the person to contact in case of an emergency, according to Carole Burton, the apartment manager. "He was very low-key," Burton said. "He didn't do anything to bring attention to himself." By the time he moved into the apartment, Clark had a driver's license, a Social Security card and several credit cards issued to Robert P. Clark, according to his rental application. He also noted he had a waterbed and a 1974 Volkswagen. Eleanor Clark, assistant prosecutor in Union County, N.J., where Robert Clark faces trial, said police do not know whether he made up an identity using fake documents or whether he assumed the identity of someone who had died. In the rental application that he filled out in 1978, Clark noted that he had been working as an accountant for nearly two years. He said he had worked for R.C. Miller & Co. of Wheat Ridge, Colo., for 18 months beginning in January 1976, but there are no tax or business records for such a company on file with the state or the city. Clark held two other accounting jobs in the Denver area, and formed his own company in 1986, according to a previous employer. But his company floundered, and Clark continued to have financial problems, according to Wanda Flanery, who said she met Clark in November 1985, when he moved in with her neighbor, Delores Miller. The couple married a month later, Flanery said. On the evening of May 21, Flanery was watching "America's Most Wanted" when she recognized Clark and told her son-in-law to call the FBI. "I prayed a lot for both of them, for their life, and then I turned them in," she said. (Garrett, of the FBI, said he could not verify whose call led to Clark's arrest.) It was not the first time Flanery had identified Clark as John List, she said. In February 1987, she said, she bought a magazine at the grocery store and read an article about the List slayings. She showed the article, and a photograph published with it, to Delores Clark. "I took it over to her and asked, 'Isn't this your husband?' " Flanery said Clark stared at the photo for a minute before saying, " 'Oh no, that's not him.' I said, 'Why don't you show it to him?' "Apparently, she tore it up. And I'm glad." Flanery said the couple had financial problems, which continued until Robert Clark, who she said always seemed to be looking for work, landed an accounting job in Richmond, where he moved in February 1988. The Clarks' $76,000 Brandermill house was listed in the name of his wife, who put down $12,000 toward the purchase, according to Betty Garter Lane, a Richmond real estate broker. The couple moved in last July, she said. Lane said Clark told her that he was from Michigan and that his first wife had died of cancer. Police said John List was born in Bay City, Mich. Following Clark's arrest, his quiet suburban cul-de-sac turned into a tourist attraction, said Patrick Ferguson, his neighbor. Delores Clark, hounded by reporters, temporarily moved to the Baltimore area to stay with family members. When she returned, Ferguson's 11-year-old son called on her to see if she needed anything. "She stopped over the next night," said Ferguson. "She said, 'The man they describe is not the Bob Clark I married.' "