Before he was caught driving with the severed head of his girlfriend in his car on Wednesday, Michael Shechtman had another girlfriend -- and she was terrified of him.

Eleven years ago, Shechtman's previous girlfriend sought and won a restraining order against him. She was breaking up with him. Shechtman threatened her life, bragged about what a good shot he was with his new gun, and told her she had "no control" over what was going to happen to her, she wrote in a sworn affidavit filed at District Court, Providence, on March 31, 1993.

In the affidavit, Melissa McCulloch wrote that Shechtman told her she was going to end up "just like" an East Providence teenager who had been raped and strangled by an ex-convict three years earlier.

"To sum up how I feel," McCulloch wrote, "I'm very scared for my life."

Shechtman would go on to own a house, be a star employee at a chemical company, and be called "brilliant" by his adviser in his doctoral program for chemistry at the University of Rhode Island.

He would also, on Wednesday, lead police, who had received a tip that he had hurt his new girlfriend, on a 25-mile chase through five Rhode Island communities before crashing in Cranston and shooting himself in the head as officers closed in.

In Plainfield, Conn., police burst into Shechtman's pale-blue house to find the headless body of a woman. Yesterday she was identified as Heather Mullins-Keltz, Shechtman's live-in girlfriend. She was 20.

An autopsy revealed Mullins-Keltz had died of asphyxia, due to compression of her neck, said the Connecticut state medical examiner's office.

Police confirmed a chainsaw had been found in Shechtman's house but it remained unclear what role, if any, it had played in Mullins-Keltz's death.

THE AFFIDAVIT at District Court, Providence, describes a man who years ago, showed frighteningly abusive tendencies.

On March 30, 1993, according to the affidavit, Shechtman, then a Providence College student who lived with his parets in North Kingstown, showed up at the workplace of his girlfriend, Melissa McCulloch.

He "blocked my car in so I couldn't get out and started to yell at me because I wouldn't return his calls and told me that I must be stupid if I was going to [expletive] with him," McCulloch wrote in the affidavit.

He told her that he had talked to his "hit man" and that he had obtained a copy of the death report of her friend, Kimberly Ann Rock. Rock was killed on Feb. 8, 1990, by a former Training School inmate who forced his way into Rock's home, where the girl was home for the day from East Providence High School, because her back hurt.

"He told me I was going to end up just like her," McCulloch wrote in her affidavit. "He also told me that I had no control of what was going to happen to me. He had all the power of what was going to happen to me. He also said I must not respect my life, if I'm gonna go against what he says to do."

She wrote that later, after she got home, he called her and started in on her again.

"He told me what a great shot his new gun was, and then he told me I was his enemy, and he always gets even with people who hurt him."

THE RHODE Island Coalition Against Domestic Violence was not surprised yesterday to learn that Shechtman had an earlier accusation of abuse. In a statement, the coalition said that murder "is at one end of a spectrum of behaviors that abusers will use to exert power and control over their partners."

The foundation of most abuse is the kind of emotional and verbal abuse described in McCulloch's affidavit, said Deborah DeBare, the executive director of the Rhode Island Coalition Against Domestic Violence.

"Emotional abuse can be as terrifying and immobilizing as an actual physical assault itself, and it's the pattern for most abusers to use emotional abuse and verbal abuse to intimidate, threaten, and put down self esteem . . . to make a person think they have no options to get out of the relationships."

"The threat of using weapons is enough to immobilize someone," she said yesterday.

And weapons Shechtman did have. In 1993, Shechtman was arrested for a felony. Police were called to his parents' house, a split-level on a shady street in North Kingstown. The alarm had tripped. The officers who entered the house didn't find an intruder, but, according to a police report, they saw fireworks, guns, syringes, and a nearly completed pipe bomb in Shechtman's room. Shechtman told the police the 93 syringes were for a science project, and that he didn't plan to finish the pipe bomb. He was charged with possession of a sawed-off shotgun and possession of a needle and a syringe. According to the police report, Shechtman legally owned an AK-47 rifle, two .22-caliber rifles, a .44-magnum semiautomatic pistol, a bow and arrow, knives and kung fu weapons.

Shechtman pleaded no contest to possession of the shotgun and syringes and was sentenced to five years of probation.

SHORTLY AFTER graduation from Providence College in 1993, he went to work for Technic Inc., a Cranston company that develops and manufactures chemicals used in electroplating electronics. He rose from lab assistant to marketing manager. He drove a company car, a black, 2002 Mercury. He was sent to Asia on business.

He was pursuing a doctorate in chemistry at the University of Rhode Island. Professor Sza Yang was Shechtman's adviser.

"He was quite a brilliant person," Yang said yesterday. "He was doing good research work scientifically."

Shechtman, 33, had already completed the necessary course work. He only needed to complete his research and dissertation to earn the degree. Yang last spoke to Shechtman in October and hadn't seen him since before the summer.

"He mentioned that he had a very busy schedule. Business for his company was picking up and he traveled a lot."

There had also been changes in his home life. About two years ago, Shechtman, about 5 feet, 4 inches, 124 pounds, with dark hair and dark eyes, bought a two-story house on rural Kate Downing Road in Plainfield. Last year, he broke up with a longtime girlfriend, whom he had planned to marry, his supervisor at Technic believed. Recently, he began dating Heather Mullins-Keltz, and she moved in.

On March 6, according to Plainfield police reports, Shechtman and Mullins-Keltz walked into the Plainfield police station to alert the police that Heather was planning to file for divorce from her husband, John P. Keltz, who serves in the Navy and is stationed at Groton, Conn.

The couple wanted the police to know, they said, because they feared John Keltz would come to Shechtman's house and try to take Heather away.

According to the police report, Heather made a point of stating that she was staying with Shechtman of her own free will.

On Sunday, say neighbors, the couple held a yard sale on the street, a country road lined with new houses, oak trees and farmland.

On Monday, Shechtman called his boss at Technic and asked if he could work from home. His boss agreed. Shechtman didn't show up for work on Tuesday either.

Plainfield police yesterday gave some information about Shechtman's last hours.

At 9:57 p.m. Tuesday -- less than 12 hours before Mullins-Keltz's headless body was found in Shechtman's house -- Shechtman called the local police department and said he was concerned about his girlfriend being with her husband, according to police reports.

Mullins-Keltz had served divorce papers on her husband earlier in the day, Shechtman told the police, and he was worried because she wasn't home yet.

What prompted the chase on Wednesday morning was a visit by Shechtman's coworker at Technic to Rhode Island State Police headquarters in Scituate. She told the police she was concerned about the welfare of Shechtman and his girlfriend. She said she had just spoken to Shechtman and that he had admitted hurting Mullins-Keltz and spoke of killing himself.

When the woman asked to speak to his girlfriend, Shechtman refused.

While at police headquarters, the woman got a call from Shechtman on her cell phone insisting that she meet him in a parking lot in Foster because he said he wanted to give her something. He promised not to hurt her.

While Rhode Island troopers went to the parking lot, a SWAT team in Connecticut stormed Shechtman's house in Plainfield, discovering the decapitated body on the second floor.

Shechtman fled when he saw police cruisers in the Foster parking lot.

With staff reports from Michael Corkery, Cathleen F. Crowley and Seth McLaughlin