EAST MILLINOCKET, Maine — As many as eight detectives have devoted thousands of hours to investigating the 28-year-old homicide of Joyce McLain since her body was exhumed and new evidence uncovered in late August, a state police spokesman said Friday.

“There has been an incredible amount of work done on this case since then and that work is continuing,” said Stephen McCausland, spokesman for the Maine Department of Public Safety.

McCausland was gently defending investigators against comments made earlier this week by Pamela McLain, the victim’s mother. McLain vented frustration at hearing no progress in the investigation from detectives despite fresh evidence unearthed by Dr. Michael Baden and Dr. Henry Lee on Aug. 29.

The internationally renowned forensic investigators were paid $20,000 she and a citizens group helped raise after the Maine Attorney General’s Office declined to pursue the exhumation.

“If they [state police] don’t have anything, perhaps they should ask someone else to help them out. There is always the FBI to help them out,” McLain said.

She added: “I want to know if the state police are capable of solving unsolved murders. If they need help and can’t do it, then I think they should ask for more help.”

Detectives have no plans to consult outside agencies, McCausland said.

A 16-year-old Schenck High School sophomore, Joyce McLain was killed sometime around the night of Aug. 8, 1980, apparently while jogging. Her body was found two days later in a power line clearing near the school’s soccer fields. Her head and neck had been hit with a blunt object.

Several suspects have been investigated — McLain places the number as high as 14 — but there have been no arrests. At least four detectives have handled the case through the years, and state police Sgt. Troy Gardner, the case’s primary investigator, has worked with several other detectives who have been on the case almost full time since September, McCausland said.

State police try to keep victims’ families informed about investigation progress but are often hamstrung by the need to keep so much of their information confidential, McCausland said. Detectives have visited McLain three or four times since August, she said, with the last visit from Gardner coming Monday.

“Details of those kinds of investigations are not something we talk about,” McCausland said. “We give as much information as we can. We update immediate family as we think appropriate.”

McLain was not impressed with McCausland’s explanations nor those expressed by Gardner when he telephoned her on Friday, she said.

“I told him that I don’t want to head-butt with the state police. I won’t do it,” she said. “I just want to stay informed as the mother. I told them that as the mother, I ought to get a little respect and know a little about what’s going on …

“I know what I am told. I am told nothing,” she added.

“I told them I am 62 years old,” McLain said. “I know what I should say and what I shouldn’t, and no one is going to keep my mouth duct-taped. I am going to keep on this.”

State police have about 70 open murder investigations dating to the early 1970s that have detectives assigned to them. Those detectives periodically review the cases, McCausland said.

In 2007, 61.2 percent of the 21 Maine homicides reported that year were cleared by arrest, according to statistics on the FBI’s Web site. That’s a fairly high percentage compared to other states, but one that signals how challenging homicide investigations can be. Clearance percentages for other, lesser crimes are dramatically lower.

No data were immediately available from McCausland or other sources Friday regarding the percentage of decades-old homicides cleared by arrest. McCausland declined to discuss the long odds typically associated with making arrests in unsolved murders.

“I would prefer to be optimistic that there is hope for each one of them,” he said of the 70 open cases.

But state police have had some successes in closing decades-old murders, McCausland noted. He cited seven homicides that were at least 12 years old when first arrests were made. One, involving the 1983 murder of Judith Flagg, 23, of Fayette, occurred because state police used new DNA technology to examine old evidence. Charged in August, suspect Thomas Mitchell Jr. of South Portland is due for trial in April.

“We never close these investigations,” McCausland said.

McLain envisioned the same success when she asked Baden and Lee to investigate her daughter’s death.

It took almost two years for her and other Katahdin region residents to raise the money to pay the doctors, the Maine Attorney General’s Office having declined an exhumation on the unlikelihood of finding new evidence. But Baden and Lee said McLain’s intuition proved eerily prescient when they found her daughter’s remarkably well-preserved body and a large amount of new evidence.

Still, the doctors warned that the evidence would take time to process and might not lead police anywhere.

Her pain at her daughter’s death is always there, but McLain said she is not obsessed. Nor will she hound detectives.

“I have great-grandkids, grandkids and a business,” said McLain, who owns a bar, Pam & Ivy’s, on Main Street. “I have a full house, a lot going on. It’s tough sometimes, but I just want to be informed. I want them to lay the cards on the table.”