CLEVELAND, Ohio -- The map is covered with Google map dots, nearly 60 of them, each representing a woman killed, a murder unsolved.

A cluster of dots forms a loose corridor along Euclid Avenue, representing women whose lives, and deaths, shared some common traits.

Are some of the unsolved deaths the work of the same killer?

Only detective work can answer that question.

But some say a computer algorithm created to spot serial killers might help.

The Cleveland area has recorded nearly 60 unsolved killings of women since 2004, and most don't appear to share the indications of a serial killer. They include drive-by and other shootings that police believe are gang- or drug-related.

Several clusters of deaths highlighted by such a computer formula, which finds common patterns of victims and killings, do share such markings.

View Cleveland Unsolved Homicides in a full screen map

Those should absolutely be explored to see if a serial killer or killers could be at work, said Eric Witzig, a retired homicide investigator for the Washington D.C. Metropolitan Police Department and for the FBI's Violent Criminal Apprehension Program (ViCAP).

The clusters involve two strings of killings of approximately a dozen women, and one trio of more widely dispersed killings of older women.

Witzig was trained by John Douglas, one of the fathers of criminal profiling. He works now with the Murder Accountability Project (MAP), a non-profit formed in 2015 to draw attention to more than 222,000 homicide deaths that have gone unsolved in the United States since 1980.

"It's not only possible that there is one series of offenses, but as many as three," Witzig, who reviewed details of the cases as part of a collaboration between MAP and The Plain Dealer.

The algorithm hit on at least 20 of the unsolved cases in Cleveland and East Cleveland, including five later determined to involve women with histories of prostitution.

Witzig cautioned that full case files, with photos and more nuanced detail of the murders, must be reviewed before firmer conclusions can be drawn.

He suggested that Cleveland ask the FBI's agency's behavioral analysis unit, based in Quantico, Va., to help determine whether one or more serial killers might be responsible for the deaths.

"Prove this is a series or prove is isn't," he said.

Cleveland police officials were interested enough in the potential patterns to discuss them with MAP over the phone last week.

"It's got us thinking," Commander James McPike, who heads the department's special investigations bureau, which includes the homicide and sex crimes unit said. "We're going to be working with the group to help us identify what we might be able to do."

About the algorithm

That thrills Thomas Hargrove, one of the founders of MAP.

Harnessing years of FBI data on homicides, Hargrove helped create the algorithm that zeroed in on the Cleveland cases.

Far more serial killers hunt in America's cities than most people are willing to acknowledge, said Hargrove, a former investigative reporter. He hopes the algorithm can be an antidote of sorts.

It uses factors like geography, the method of killing, and the age and gender of the victim to highlight unsolved killings that have higher odds of being the work of a serial killer.

Hargrove hopes the algorithm, which is available for free on the MAP web site, also can help reverse a worrisome decline in the number of homicides solved in most cities -- one that erodes confidence and community trust, and may embolden killers.

The algorithm already has spotted patterns that Hargrove believes could have saved lives.

In 2010, as Hargrove was refining his algorithm, he found a cluster of more than a dozen killings in Gary, Ind. with strong signs of connection.

The victims were women, mostly young adults. All were strangled; many of their bodies were recovered in abandoned buildings or vacant properties.

Hargrove sent emails and registered letters urging police to investigate, but never heard back. Four years later, a man was arrested for the murder of a 19-year-old woman at a motel in a neighboring city. The man lead police to abandoned buildings in and around Gary where he'd hidden six more bodies.

All seven victims discovered in 2014 died after Hargrove sent his letters. It's not clear whether police believe the killer is responsible for the earlier killings. They won't comment and are now bound by a judge's gag order until the case goes to trial.

Hargrove first spotted an alarming pattern in the Cleveland area when he was looking for serial hotspots at the request of two documentary film makers who produced "The Killing Season," which aired starting in November on A&E.

Styled as an investigation into the unsolved Long Island Serial Killer case, the series raises larger questions about how many undetected serial killers there are nationwide and why so many cases remain unsolved.

After that series, and a 4,000-word article in Bloomberg Businessweek earlier this month, Hargrove got calls from Hollywood types pitching a "Moneyball" meets "Silence of the Lambs" blockbuster.

Right now, he's still more interested in talking to cops.

Cleveland's homicides

His attention returned to Cleveland last month when, on her way to school, 7th grader Alianna DeFreeze was snatched off the street. She was found dead days later, beaten and stabbed, in an abandoned home on Fuller Avenue.

Four other women were murdered along East 93rd Avenue since 2012. Alianna's death stoked fears that she, and they, were victims of the same killer. Those fears were amplified by nightly news coverage and by Councilman Zack Reed, who said police were being "taunted" by a serial killer.

The department swiftly arrested Christopher Whitaker, 44, a sex offender. They are confident he is responsible for Aliana's killing, based on strong DNA evidence.

Whitaker has pleaded not guilty in Alianna's death. He was in the county jail when at least two of the other four women were killed. Police haven't ruled out the possibility that he's connected to other cases, though.

Hargrove wonders about that, too. Especially based on the particularly brutal nature of the crime.

"If this is the right guy, what are the odds he killed for the first time at age 44?" he said.

And if not Whitaker, there could be others.

Part of what got Hargrove interested in Cleveland was something strange in what the city reported - or didn't report - to the FBI.

Since 2003, Cleveland hasn't reported a single strangulation murder, of which there have been more than 30. The department also didn't report details of the the murders of 11 women Anthony Sowell killed in 2009 to the FBI's Supplemental Homicide Report (SHR).

The chart shows Cleveland homicides of women reported to the FBI Supplementary Homicide Report that were labeled as "unknown." Some of those deaths were strangulation deaths.

What departments report to the FBI is voluntary, and definitions of "homicide" vary.

The number of homicides Cleveland records locally, though, and what it reports to the FBI is are rarely close.

In 2014, Cleveland reported handling 102 homicide cases but reported 63 to the FBI. The Cuyahoga County Medical Examiner's office logged 104 homicide cases in Cleveland.

McPike said he'd look into the discrepancies.

The department is among the worst in the county at accurately reporting murders, Hargrove said. Despite the likelihood of missing cases, he added, "Our systems are flashing 'red alert' for serial killers."

Because Cleveland's information was incomplete in the FBI database, Hargrove worked with The Plain Dealer over two weeks to match information on women killed in Cleveland and East Cleveland since 2004 to more detailed medical examiners' data, and determine which cases were still unsolved based on FBI data and local news reports.

That was combined with with information on vacant lots and abandoned homes, common dumping grounds in serial cases.

Connecting the dots

Some of the cases the algorithm identified, on closer examination, seemed to have deeper connections.

When the crime scenes were plotted on a map, two general "corridors" emerged.

One was a cluster of cases grouped along East 93rd Street, where Alianna was found last month. The second was a grouping of cases running both north and south of Euclid Avenue, from Cleveland into East Cleveland. Those areas also have a number of unsolved rapes.

A dozen of the murder cases involved victims who had a history of soliciting, which made them more vulnerable targets.

Of the 12 cases in the two corridors:

Nine were in Cleveland and three were in East Cleveland.

Seven women were found in vacant lots or abandoned homes.

Nine were killed by strangulation, blunt-force trauma or stabbing.

Serial murderers often prey upon those leading high risk lifestyles, said Enzo Yaksic, who also works with MAP and has researched serial killing for more than a decade, helping to build the first serial homicide offender database.

Such offenders count on victims "not being missed." The offender in at least some of the Cleveland cases likely "lives, works and prays in the same community from which he selects his victims," Yaksic said.

East Cleveland police used DNA evidence to connect two men to a shoestring that in 2008 was used to strangle one of the women, 24-year-old Lu Jean Darnel Frazier. A judge later dismissed the case against one of them. He can't be re-tried. The other suspect remains uncharged.

In one of the other unsolved cases, Sandra Varney, a well-known prostitute called "Little Bit" was strangled in her motel room with a cord. Detectives working the case don't doubt the killer could have other victims. East Cleveland has DNA from the crime scene belonging to an unknown male.

East Cleveland Detective Bureau Chief Scott Gardner said his department is open to using technology, including computerized data analysis, to help solve cold cases or make connections to similar cases in neighboring cities.

Cleveland police also may have leads or suspects in some of their unsolved cases which investigators haven't discussed in public.

Rate of solving homicides declines

There's another good reason for Cleveland to consider getting extra help.

Cleveland's rate of solving homicides has plummeted from more than 75 percent in past decades- above the national average - to about 45 percent in the last five years.

It's the same type of decline seen across the United States, despite improved technology, especially DNA and crime analysis tools, that should be helping to solve more murders.

Those tools, though, don't substitute for time and detective work, experts say. Cleveland's homicide unit has lost many experienced investigators to retirement in recent years. It has only 13 detectives today; it handled 136 cases last year.

Cleveland's detectives get new cases just about every shift, creating a conveyor belt that deprives them of time to look back at older cases.

A lookback at cold cases has yielded unexpected results in the past.

After Anthony Sowell's arrest for the murders of 11 women in November 2009, then-county prosecutor Bill Mason assembled a special project called the "Sowell surge" to look at other cases he might be responsible for.

Investigators from the office's cold case unit reviewed more than 75 unsolved homicides of women whose bodies were found within 2 1/2 miles of two homes were Sowell had lived.

DNA evidence was sent to the Cuyahoga County Medical Examiner's office for testing in more than 30 cases. None were matched to Sowell. But the evidence did help convict another serial killer, Joseph Harwell, who was already in prison for strangling and raping Teresa Vinson in Columbus 1997.

In 2011, Harwell was convicted of murdering Mary Thomas, who was four months pregnant when she was found in an alleyway, beaten and strangled to death with a cord. He also admitted to killing Tondilear Harge, whose body was found in some woods near East 86th street in 1996. Both Vinson and Thomas were found naked from the waist down - except for a pair of clean white socks.

A second man, Jerome Wade, was also convicted of the 2006 killing Mary Hudson in East Cleveland. Hudson was strangled and hog-tied using a stocking.

Since then, the cold case unit has continued to dig into unsolved homicide and rape cases going back decades that might be solved by testing DNA.

"The office has worked closely with the local FBI and the Behavioral Analysis Unit on several of our Cold Case Investigations," Ryan Miday, spokesman for County Prosecutor Michael O'Malley said. "If new information is provided to us from any new technology or analysis, we would be interested."