Case 53 DNA evidence

For anyone interested further or wanting some clarity on the DNA evidence in Case 53, written by Anna:

1. The DNA collected in Southern California murders matched 3x Contra Costa County mixed semen samples. Thus linking Southern California to Contra Costa.

2. All Contra Costa County cases were linked to Sacramento by MO only, one of the reasons to describe details of every attack was to present the evidence showing why investigators have linked all attacks.

3. Much of the physical evidence from Sacramento cases has been destroyed, likely the reason the "Excitement's Crave" poem has no original. Some detectives like Bevins did keep files and Shelby did too, but has since passed them onto current detectives.
 It was routine practice to destroy evidence after a certain number of years/ statute of limitations runs out on a case. Not a 'mistake' made at the time.

4. The semen samples—for which there is not much left of—were mixed samples. This means they separated the females DNA from the EAR/ONS in order to get his DNA profile.

5. The Nationwide CODIS system in USA is cross checked every year (or more) for new matches; they have been checking for 17 years.
 The last search was across over 16 million profiles.

6. The likelihood of getting a new direct match is slim because the probability of a 60+ year old committing a felony is small. There is a higher chance of getting a close familial match at this point. 

7. Not all states have the same laws as to which criminals have their DNA taken. In California, it’s all people arrested for a felony but this is not the case across the whole country.

8. All states have a DNA database according to their own laws, and they send their results to the FBI national system.

9. The DNA evidence has also been fed into the Interpol worldwide database which covers numerous countries own database (including Australia). This is not routinely done with familial searches as this is an entirely different area of DNA matching.

10. The military have no database for DNA samples for criminal matters. Any DNA samples taken from their members have been stored for the purpose of soldiers possibly needing to be identified as a result of death in action.

11. The California DOJ will permit law enforcement to also conduct a “familial search” of the system for any people who have the potential to be closely related on the father’s side. This is a close relative. When California passed the law to allow familial searches, the first person’s DNA to be uploaded to the system was the EAR/ONS. This continues to be checked.

12. There are other types of DNA testing which includes Autosomal DNA testing, in private labs which also have separate, private databases. 
But because the DNA samples are mixtures, meaning a mix of the EAR/ONS DNA, as well as the females DNA and the forensic genealogy labs, do not work with mixed samples, there is too much room for error and so labs don’t tend to work with mixtures.

13. Investigators cannot check private databases at this time nor can they cross check with private genealogy services like ancestry.com (privacy/legal reasons). Public databases, however, have and continue to be checked. If there was a serious suspect, yes, a warrant could be obtained.

14. By people in the community continuing to pursue personal genetic genealogy, like 23andMe, uploading their DNA to databases in order to trace their family history, a more distant relative may be found in the future.

15. Investigators currently have different means of collecting DNA from a POI (Person of Interest), they ask the person to volunteer if they believe it wont harm the case. They can ask family members to offer their DNA, they can apply for a warrant, they can collect a sample discarded by the suspect on public property if the sample was obtained according to the correct legal process.

16. Phenotyping is possible. This is the digital facial image that can be established to resemble the person from their genome. It delivers a composite based on hair colour, skin tone and other characteristics determined by genes. It can show whether the person is of mixed ancestry and where that ancestry lies. There has been no confirmation this is happening but it is possible. This has helped recently in cold cases but there is also evidence that it has hindered, when the perp was found and didn't resemble the image greatly.