Can washing remove DNA evidence?

Yes and No

Washing can reduce or remove DNA in some situations, but it does not guarantee that biological material will be eliminated.

Research has shown that DNA may persist on clothing and other materials even after washing. The outcome depends on factors such as the type of fabric, the amount of biological material present, washing temperature, detergents used, and whether items were washed more than once.

In some cases, washing significantly reduces detectable DNA. In others, small amounts may remain and still be recoverable through laboratory testing. The absence or presence of DNA after washing is therefore not predictable.

Importantly, finding DNA on a washed item does not establish when it was deposited or whether it relates to a particular event. Biological material can persist from earlier contact or transfer during handling, storage, or laundering.