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Unit looking for ‘Speed Freak Killers’ victims
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When San Joaquin County Sheriff Pat Withrow assuming his current position in 2018, one of the first things that he did was create a “cold case” unit to review unsolved crimes from throughout the county and help identify missing persons.

And that is exactly what the unit – which now includes two detectives, a full-time deputy, and a sergeant – is doing.

In a statement that Sgt. Linda Jimenez released last week updating the public on the group’s developments, the addition of a full-time deputy to the group has allowed for 10 missing persons to be tracked down throughout California and the rest of the country – all of them determined to be alive and well.

The detectives have been working cold cases individually and the group of four has been working together on developments in the case of serial killer Wesley Shermantine – one half of the “Speed Freak Killers” that authorities believe were responsible for nearly 20 murders and could be responsible for dozens more in and around the Linden area in the northeastern part of the county.

“Our unit has been working very hard and will continue to do so. This process is slow as the cases need to be reviewed more than once to have a good understanding of the crime, parties involved, evidence, and more,” Jimenez wrote in a letter outlining the progress of the group. “They have been writing search warrants for information from various companies but since the information that they are asking for is older, the results are taking longer.

“Our goal is to expand the unit but due to attrition and filling vacancies on Patrol that might not be possible for some time.”

The Shermantine case, which attracted national attention, is requiring detectives to go through letters that the convicted killer – who is currently on California’s Death Row – had written and maps that he had drawn has sparked visits to a number of sites where remains could be located. The unit is working with experts on how to incorporate technology like ground-penetrating radar, dogs, and probing techniques before attempting to recover the remains of potential victims.

Bones that were recovered in past searches under the previous administration have been sent to an anthropologist to determine whether they are animal or human, although the pandemic is delaying that information from making it back to investigators at the moment.

And the unit is working to clear the backlog of cases that qualified for their assistance.

While cases like the Shermantine one will take an extended period of time to work, others have already been forwarded on to the San Joaquin County District Attorney’s Office for consideration of charges or dismissal, and others have been moved towards dismissal because all of the involved parties are now deceased.

To contact reporter Jason Campbell email jcampbell@mantecabulletin.com or call 209.249.3544.