The mayor of this Chicago suburb knew he was a marked man.

He had written a note that said, "I was to be executed on Tuesday but I got a stay of sentence and I am now on probation," and left it in his desk drawer in the village hall.

Mayor William Hawkins' "probation" ended shortly before midnight Oct. 16 as he arrived home from work at a nearby steel plant. As he stepped from his car in the driveway beside his modest home, he was hit in the left thigh, left arm and right kidney by three of six bullets fired from a .233 caliber combat rifle.

Two hours later the suburb's police dispatcher received a call from a man who said, "Listen ma'am . . . I missed the mayor tonight. I missed him good. If that police commissioner appears at another meeting, he's next." h

A few minutes later the phone rang in the home of Robert S. Howell, chairman of the village board's police and fire committee. A male voice said, "I just shot the mayor, and if you don't resign, you're next."

Two days later Hawkins died, after telling investigators he hadn't seen and had no idea who his assailant was. Cook County sheriff's detectives have interviewed more than 200 persons since then but still aren't close to solving the crime.

One area of investigation has been the Phoenix Police Department, which had staged a four-day strike two weeks before Hawkins was killed. During the strike a bullet was fired into Hawkins' home.

The strike was over Hawkins' efforts to fire six policemen whose salaries had been paid through federal Comprehensive Employment and Training Act grants that expired Oct. 1. Hawkins eventually agreed to pay the officers out of village funds.

But the resentment lingered, sheriff's officers say. They say some Phoenix officers also resented Hawkins' efforts to professionalize the department of seven full-time and 14 part-time policemen, some of whom come to work only when they feel like it.

"We're not getting the best of cooperation from members of the police department," said sheriff's Sgt. Arthur Jackson. "That's not to say they're involved in the shooting, but we've had difficulty getting them in for interviews."

Phoenix policewoman Michelle Harvey said Jackson was partly correct. "The reason we're not cooperating is that the sheriff's people won't treat us with respect," she said. "They harass us and try to confuse us. They constantly tell us we're not suspects, but then they treat us like we are."

Phoenix, three miles south of the Chicago city limits, has 3,700 residents, 87 percent of them black. It ranks 197th out of 205 Chicago suburbs in family income.

Because official corruption is not unknown in the Chicago suburbs, particularly the poorer ones, investigators wondered whether Hawkins' assassin might have used the police unrest as a cover to settle a score on an unrelated matter.

So they audited the village's finances but found nothing worse than sloppy bookkeeping.

Interviews with contractors turned up no evidence of payoffs.

Detectives also discount published speculation that underworld figures might have killed Hawkins as part of an effort to muscle in on village rackets.They say vice in Phoenix consists of little more than a frequently raided whorehouse and some dice and poker games -- hardly enough to interest the Chicago crime syndicate.

They also investigated the possibility of a love triangle, standard procedure in cases such as this, but have ruled it out. Hawkins, 57, married and the father of five grown sons, apparently led a private life that was as blameless as his public life.

He had been a member of the village board since the 1950s and mayor since 1973. His only previous major appearance in the news was in 1977, when he tried unsuccessfully to persuadethe federal government to build a public housing project in the village so that some residents could move out of what he described as "their rat-infested homes."

"I got to know the mayor during the negotiations over the police strike," said Jackson of the Cook County sheriff's department. "I found him to be a dedicated, articulate, intelligent person who liked what he was doing.

"But he obviously made some enemies."