PORTLAND – Investigators don’t believe a serial killer was responsible for the slaying of a Massachusetts woman whose body was found in a trash barrel last fall in York County, but they’re no closer to solving the crime.

The body of Wendy A. Morello of Worcester, Mass., was found in a green trash barrel off Riverwood Drive in the town of York on Sept. 13. Police believe she was killed somewhere else and her body later was discarded in Maine.

One of the key challenges in the Morello case is not knowing where she was killed before her body was left in York, investigator said.

The lack of progress has frustrated family members who are unable to put the 40-year-old woman’s murder behind them.

“Certainly we are looking for closure here,” said Morello’s father, Leo Morello. “The thing is we get no answers. Nothing.”

Morello’s history of drug use, prostitution and life on the streets in Worcester led police to consider the possibility she could have been the latest in a string of killings that targeted women living and working in that neighborhood.

Like Morello, the women were petite, had substance-abuse problems and sometimes turned to prostitution in Worcester’s Main South section to support their habits.

“There were a number of similarities. That was the reason we initially looked at it,” said Melissa Sherman of the Middlesex County District Attorney’s Office. “Upon further investigation, it didn’t appear to be related to our cases.”

Middlesex County led a task force looking into the murders of three women whose skeletal remains were found in 2003 within a mile of each other in the suburbs outside Worcester.

Despite the similarities, there were significant differences, said Maine State Police Lt. Brian McDonough, who leads the criminal investigations division for southern Maine.

Morello was taken to Maine, 100 miles from where she last was seen and where the other bodies were found. Rather than being buried in the woods, as were at least two of the other victims, her body was left in a plastic trash barrel.

The bodies outside Worcester were decomposed. Authorities are working with forensic scientists at the Smithsonian Institution to determine how they died. Police have not released Morello’s cause of death.

“Are they connected or are they not connected? You just can’t say absolutely one way or the other,” McDonough said.

In an effort to jump-start the investigation, Maine police this past winter provided a Boston television program about unsolved crimes with pictures of the Dumpster and an extra-large kitchen-worker’s shirt found with Morello’s body.

Morello’s death remains a Maine case because her body was found here, though Maine detectives have worked closely with Worcester police.

Maine Deputy Attorney General William Stokes said the investigation into Morello’s death remains active. “I hate to refer to anything as a dead end,” Stokes said. “It’s fair to say that as time goes on, cases get more difficult to solve.”

Morello’s father said he is frustrated that investigators have not made more progress.