The first signs of trouble were thousands of antisemitic leaflets, left mysteriously at area high schools on Adolf Hitler's birthday this spring. Then three synagogues in Sacramento were torched, an abortion clinic firebombed, a well-known gay couple shot dead in their bed.

A wave of hate has been spreading through the usually tranquil valley towns of Northern California for the past few months, and although the cause of each incident is still being investigated, federal and local law enforcement officials here now say they believe they have two prime suspects in custody.

Benjamin Matthew Williams, 31, and James Tyler Williams, 29, are in jail, and police say they are preparing to charge them with murder, and possibly other racially motivated crimes, later this week. As investigators continued today to probe their possible role in all of the attacks, as well as links the men may have to white supremacist groups nationally, more details of their lives emerged.

The two brothers grew up in the small California town of Gridley, north of Sacramento, and were raised in a fundamentalist Christian family that moved to Redding a few years ago. Some people who know the family said today that the father of the suspects, Benjamin Williams, was a strict disciplinarian who often loudly professed extremist views to neighbors.

"It was an unusual family," said David Anderson, a high school teacher who bought their house in Gridley when they moved. "Everything they did was about religion. They were fanatical about it."

Anderson said he never heard the father or his sons explicitly preach hate over the months that he dealt with them. But he said that mail from militia groups addressed in their name continued to arrive at the house long after they moved to Redding on what Anderson said the father told him were "God's orders."

Neighbors also said that the family went to great lengths to keep to themselves. They grew most of their food in a sprawling yard complete with an organic garden and chickens, and educated both brothers at home until they reached high school, where they were forbidden to participate in extracurricular activities.

In recent years, the brothers, who police say have no prior criminal records, pursued what some here describe as a longstanding interest in horticulture. They bought and sold plants at a farmer's market in town that one of the slain gay men had founded, and had been attempting to start a landscaping business. The older brother, known here mostly by his middle name Matthew, was a quiet fixture on the weekends at the farmer's market, according to vendors there.

"He was really into selling unusual edible plants," one vendor who asked not to be named said today. "That's all any of us really ever knew about him. He came and went pretty quietly."

When they were arrested in a shopping mall parking lot last week, both brothers were carrying loaded semiautomatic pistols and one was wearing a bulletproof vest. Several assault rifles and a shotgun were found in the trunk of their car, police said, and the men had just purchased five large cases of ammunition--all with a credit card issued to one of the gay men who had been killed near here a week earlier. The Record Searchlight of Redding today quoted the store owner as saying the brothers had so much ammunition they "had to make three trips" to put it all in their car.

Later, during a search of the brothers' ramshackle home, police said they found a notebook containing the names of more than 30 prominent members of the Sacramento synagogues that had been burned, as well as racist, antisemitic propaganda from an extremist group known as the World Church of the Creator. Benjamin Smith, who went on a racially motivated shooting rampage through Illinois and Indiana over the Fourth of July weekend before killing himself, also was an adherent of that group.

The Anti-Defamation League has called the World Church of the Creator, which is based in Illinois but has several chapters in California, one of the most dangerous hate groups in the nation. Matthew Hale, who leads the atheist group, has denied having a role in any of the recent attacks in Northern California.

This part of the state, which is mostly rural, has been a hub for militia-style extremist groups in the past, but in recent years has seemed to show more tolerance. Police say that until the past few months, hate crimes have not been a problem in the area. Redding has a small but vibrant gay community whose members have told the local media over the past few days that they have rarely faced hostility.

The two slain men--Gary Matson, 50, and Winfield Mowder, 40--had been living together near here for 16 years and both were active in the community. Matson was particularly well known. He helped create a natural science museum and an arboretum here, and he founded the weekly farmer's market in town. Mowder worked in the plants department of a hardware store and had just earned a degree in anthropology. Residents here say it was no secret that the two men were gay, but that they by no means were activists about it.

"It just never came up," said the vendor at the farmer's market. "They were beloved by many people here because they were real community builders. They were only outspoken about horticulture."

CAPTION: Winfield Mowder, left, and Gary Matson were killed in their Happy Valley, Calif., home. Police say the Williams brothers will be charged.

CAPTION: James Tyler Williams, left, and Benjamin Matthew Williams were raised in a strict Christian family and had taken a strong interest in plants.