Locard's Exchange Principle - Famous Cases - The Westerfield-van Dam Case

The Westerfield-van Dam Case

Danielle van Dam, aged 7, lived with her parents and brothers in San Diego, California. She was reported missing on February 2, 2002; her body was discovered on February 27. Neighbor David Westerfield was almost immediately suspected, as he had gone camping in his RV, and he was convicted of her kidnapping and murder.

Hairs consistent with the van Dams’ dog were found in his RV, also carpet fibers consistent with Danielle’s bedroom carpet. Danielle’s nightly ritual was to wrestle with the dog after getting into her pajamas. The prosecution argued that those hairs and fibers got onto her pajamas through that contact, and were then carried on the pajamas to first Westerfield’s house and then to his RV, when he kidnapped her from her bed. The alternative scenario is that they got onto her daytime clothes, and those of her mother and younger brother, and were carried to his house when they visited him earlier that week selling cookies. He said his laundry was out during that visit, so trace evidence from them could have got on it, and then been transferred to his bedroom and his RV (secondary Locard transfer). Also, his RV was often parked, sometimes unlocked, in the neighborhood streets, so Danielle could have snuck inside, leaving behind that evidence.

A detailed examination of the trace evidence may decide between the guilty and innocent scenarios.

No trace of him was found in the van Dam house.

14 hairs consistent with Danielle’s were found in his environment. All but one were compared on only mitochondrial DNA, so they might have come from her mother or a sibling. Danielle had a haircut shortly before the cookie sale, so any frayed hairs (split ends) were likely from a prior time, but this was not revealed. Also not revealed was which surface of particularly his fitted sheet those hairs were on: the underside would not have acquired hairs from someone laying in the bed. Her hair was darkening, yet all three hairs in the RV were blonde, suggesting they were old and therefore from a prior sneak visit. There were many more hairs (human and dog) in his house than his RV (30 to 8), suggesting the latter was from secondary Locard transfer. Most (21) of the hairs were in a dryer lint ball in his trash can, so they might have got in his laundry before the kidnapping.

There were 5 carpet fibers in his RV, but none in his house, suggesting those were deposited by someone going directly from her house to his RV, or they may have come from another house in that development.

No Danielle pajama or bedding fibers were reported in his environment (which casts doubt on the belief that the dog hairs and carpet fibers were shed from her pajamas). There was no trace evidence in his SUV (which casts doubt on the belief that she was transported from his house to his RV in his SUV). He vacuumed his RV after the kidnapping, but no trace evidence was in the vacuum cleaner.

One orange fiber with her body was consistent with about 200 in his house and 20 in his SUV (none in his RV), while 21 blue fibers with her body were consistent with 10 in his house and 46 in his RV (none in his SUV). Contrary to media reports, only a few items from her house were tested so that can’t be excluded as the source. In particular, the clothes of Danielle and her family during the cookie sale were not determined and eliminated. There were apparently two different types of the orange fibers, dull and very bright (so the number which matched might have been much less than 200). None of the blue fibers were fully tested (so they might not even have matched). They are also probably relatively common (so those in his environment might not have come from the same source as those on her body). There were no Westerfield bedding fibers with the body. There were red fibers with her fingernails, and many other fibers with her body, which could not be matched to his environment. The only non-Danielle hair found with her body wasn’t his, nor was any desert sand reported with the body, and no soil or vegetation from the dump site was reported on his shoes, laundry, shovel or RV.

To explain why so much expected evidence was missing, the prosecution claimed he went on a cleaning frenzy, and tossed out evidence.