Man arrested for murder in Seattle case where woman’s body was found in suitcase

The Washington State Patrol (WSP) announced Thursday afternoon it made an arrest for murder in the case of a woman whose body was found in a suitcase in a Seattle homeless encampment last month.

In a statement sent to members of the media, including KIRO Newsradio, the state law enforcement agency said troopers arrested Steven Thanh Nguyen, 57, for the murder of Shannon Marie Caslin-Reeder, 37. Nguyen has been charged with second-degree murder, WSP added.

Previous coverage: Dead body found in suitcase near I-5, I-90 interchange identified

Nguyen lived in the same encampment where Caslin-Reeder’s remains were found, WSP explained. Investigators established that Caslin-Reeder visited Nguyen at the encampment but had housing at another location. Detectives were able to establish that the last confirmed local sighting of Caslin-Reeder was in November 2023.

The suspect was arrested on a separate Department of Corrections warrant Oct. 3, and was later interviewed regarding the Caslin-Reeder case. Detectives then found evidence of the suspect’s alleged involvement in the homicide, WSP explained. From there, the case was submitted to the King County Prosecuting Attorney’s Office and charges were filed Wednesday.

Caslin-Reeder’s body was found at a homeless encampment near the Interstate 5 (I-5)-Interstate 90 (I-90) interchange in Seattle Sept. 27.

That day, workers clearing the encampment first noticed an odor, then discovered the woman’s badly decomposed body. Online reports from independent journalist @PhotogSteve81 on Instagram at the time said the body was that of a woman, and the body was found inside a suitcase. However, WSP wouldn’t confirm the details at the time.

“Death in the outdoors and especially death at the hands of someone who has done evil to another person can create great indignities to a human body and this body suffered those indignities,” WSP spokesperson Chris Loftis previously told KIRO Newsradio.

More information on Caslin-Reeder’s death

Referring to charging documents it acquired, KIRO 7 reported forensic experts determined Caslin-Reeder “suffered multiple sharp-force injuries, primarily to the neck and skull, which were consistent with wounds inflicted by a weapon like an axe or hatchet.”

The investigation revealed that Nguyen had allegedly assaulted Reeder with a sharp object during an altercation, the Seattle media outlet explained.

Nguyen and Caslin-Reeder apparently shared a volatile relationship, KIRO 7 stated in its reporting. Witnesses described seeing the two together in the months leading up to her death, and some indicated prior domestic disputes between the pair took place.

The exact nature of their relationship is unclear, but prosecutors believe that an argument may have led to the fatal assault.

Initially, Nguyen claimed Caslin-Reeder overdosed on fentanyl, then claimed she fell on some rocks, KIRO 7 reported. But detectives noted her injuries were inconsistent with this explanation. Nguyen’s story quickly unraveled after that.

According to investigators, after Caslin-Reeder’s death, Nguyen placed the woman’s body in the suitcase and attempted to conceal it under his bed for several months.

More from crime blotter: Covering the crimes committed in the Puget Sound region

The suitcase was eventually discarded at the encampment, where it was discovered by residents who reported it to authorities, according to KIRO 7.

Nguyen has a lengthy criminal history, which prosecutors highlighted in their request for a $2 million bail.

Editors’ note: An earlier version of this story had a different spelling of the suspect’s last name. The story has been updated with the correct spelling.

Contributing: KIRO 7; James Lynch, KIRO Newsradio

Steve Coogan is the lead editor of MyNorthwest. You can read more of his stories here. Follow Steve on X, or email him here.