DETROIT (Det. Free Press) -- As bulldozers started to take down the Park Medical Centers building on Grand River in Detroit today, friends and family of Sharita Williams, 35, said they feared she was killed inside.

According to some of Williams' cousins and friends, the woman was working inside the building as a medical assistant when the shooting and fire happened. She hadn't been seen since.

Detroit police confirmed a woman's body was found in the building, but have not released the identity.

Workers were evacuated this morning after reports of gunfire and arson at the site in the 8000 block of Grand River, near West Grand Boulevard.

Williams had been dating a man she met at work, said Angelo White, 32, her ex-boyfriend and longtime friend. After about six months, he said, she decided to break it off but had trouble with the man, who White identified as Myron Williams. The two were not related. Sharita Williams has four children, said White.

"She wanted to go on with her life," said White.

An official familiar with the investigation said authorities believe Sharita Williams and Myron Williams were inside the building. Myron Williams' body has not been found, the official said.

A man walked into one of the offices around 9 a.m. and started shooting, authorities said. He is believed to be a former maintenance employee.

Lanier Alfaro, an office manager at a podiatrist office in the building, said she was told the man had targeted a woman who worked in the building. Property restoration workers said the fire was intentionally set.

"It was devastating," Alfaro said.

Detroit police Inspector Dwane Blackmon, head of homicide, would not offer details on what happened, but said "there was some type of altercation, some type of problems prior." A DTE Energy spokeswoman said that gas to the building was shut off at 10:17 a.m.

The fire apparently claimed the extensive boxing memorabilia collection of former Michigan Boxing Commissioner Dr. Stuart Kirschenbaum, who had a podiatry office in the building.

Dr. Stuart Kirschenbaum stood with his family, watching bulldozers take down the building he had worked in for 30 years. He said when he arrived at 6:45 a.m., he saw the maintenance man believed to be the shooter, but that was normal. He said about 8:30 a.m., security guards in the building came and ushered them out, saying the maintenance man had taken two women hostage and had shot one before heading down to the basement.

"The killings, then burning the building down. It's just affected thousands of people," he said, noting the clinic was one of the largest healthcare providers in the area.

Patients looked on too. Antionette Stroble, 55, said she returned to her neighborhood from the far west side of Detroit for her doctor, Dr. Richard Brown. She said she had no idea what she was going to do for health care now.

"That's a good question," she said.

By Gina Damron, Eric D. Lawrence and Megha Satyanarayana