Hi Alexander, 

Can you tell me what part of Colorado you found this in, and why it was removed? This will help me narrow things down. 

From a first glance, it appears to be a type of longhorn beetle larvae (Family Cerambycidae). Most only feed on rotting wood, but there are some species that can be a problem (e.g. pine sawyer), particularly for the exotic pines (i.e. austrian, scots pines). It could also be the larvae of the western sculpted pine borer. If possible, a close-up picture of the mouthparts would help (but I assume you no longer have the larvae). 

If the pine was declining from the top down, then the beetle may be the cause of the decline. If the decline was not as localized, it's probably one of the many longhorn beetles that is just a symptom of the decline. 

The top-down decline I'm alluding to is called pine wilt, a nematode vectored by the pine sawyer. These symptoms should be confirmed with the homeowner before initiating management. Here is more information about pine wilt:

https://extension.colostate.edu/topic-areas/yard-garden/pine-wilt-disease-2-915/#:~:text=What%20is%20Pine%20Wilt%3F,sylvestris)%20and%20Austrian%20(P.