The manner of death for Washington University senior Yongsang Soh, who fell from a 23rd-floor balcony last year, has been changed to “undetermined” after originally being ruled a suicide.

Soh fell from an apartment in The Dorchester on Forest Park on the morning of Oct. 26, 2013. His parents soon opened a private investigation into his fall, which has turned up evidence they think suggests the University played a part in Soh’s death.

The family’s argument centers on the University’s allegedly lenient behavior toward the Sigma Alpha Mu fraternity, of which Soh was an active member before its derecognition in July 2012. In exchange for keeping its concerns over the University’s handling of SAM drug violations private, the Soh family requested a payment of $50 million and the promise of changes in the University’s student discipline procedures.

The University rejected the proposal, and the Soh family’s local attorney, Albert Watkins, said he anticipates filing a lawsuit in the Circuit Court of the City of St. Louis later this week.

Michael Graham, chief medical examiner for the City of St. Louis, confirmed that the manner of death was changed as a result of an independent examination of the body pursued by the Soh family, which found LSD in Soh’s system.

Graham explained that an initial toxicology screening wouldn’t have discovered LSD and that a specific screen for LSD would be needed to find traces of the drug.

Soh had consumed multiple tablets of LSD on the night of his death, alleged a document that the Soh family delivered to the University in June outlining the circumstances surrounding Soh’s death.

The Washington University school flag over Brookings Hall flies at half mast in honor of senior Yongsang Soh on Nov. 2, 2013. The flag flew at half mast following Soh’s death from a 23-story fall from a Dorchester on Forest Park apartment balcony the previous weekend.

The document connects the presence of LSD in Soh’s system to SAM. Sigma Alpha Mu had been one of the University’s oldest fraternities before running into trouble for hazing and drug violations in recent years, ultimately culminating in the chapter’s closing in 2012.

A Student Life article from 2002 reported that SAM had been suspended for two years in 1999 for violations including “poor leadership, financial woes, troubling behavior and alcohol abuse, culminating in accusations of hazing stemming from SAM’s spring pledge events.”

SAM was disciplined again in 2008, when a drug bust at the chapter’s house led to the arrest of three members and the fraternity’s eviction from Upper Row.

The fraternity continued to operate off campus until 2012, when a months-long investigation into drug activity and dealing among SAM’s members led to the fraternity’s national organization disbanding the Washington University chapter. Four days later, the University officially withdrew its recognition of SAM.

It was between the latter two disciplinings, in 2010, that Soh enrolled in the University and joined the fraternity, the family’s letter states. The document further states that the night of his death, Soh spent time with a number of students associated with the SAM fraternity.

“The last hours of Soh’s life were spent…engaging in drug fueled interaction with his SAM House compatriots (many of whom had been identified by The University as being involved in criminal activities, the SAM House, drug possession and distribution[)],” it says.

Watkins emphasized that Soh had no history of drug use before becoming involved with SAM.

“He was not a drug user; he had no history of drug use; he had no prior predisposition to alcohol abuse or drug abuse. And that’s what struck the Soh family as being completely out of the ordinary,” Watkins said.

The family claimed that by joining SAM at the University, however, Soh was exposed to a group “with a longstanding and notorious history of drug use, distribution, and exploitation of minors.”

“The University chose not to refer these matters to the proper authorities for criminal prosecution as would otherwise be required by any other law enforcement authority,” the document continued.

Jill Friedman, vice chancellor for Washington University’s Office of Public Affairs, refuted the notion that the University was too lenient in handling drug cases, particularly the 2012 SAM investigation.

“The university took serious disciplinary action against involved students – up to and including permanent termination – and referred individual cases to the local prosecutor for consideration of criminal charges,” Friedman said in a statement.

The University would not comment further about specifics of Soh’s case or the letter because it involves a pending legal matter, Friedman said.

Other information that the letter presents as evidence against a potential suicide included a private investigator’s finding that Soh had not searched for any terms relating to suicide on his laptop in the days preceding his death. Instead, the document continues, Soh had spent that time shopping online and purchasing tickets for a baseball game to be played after his death.

According to the letter, the Soh family operates a chain of Papa John’s restaurants in South Korea, and they expected Yongsang Soh to take over the business in the future. Watkins said that the $50 million amount was chosen to be a financially meaningful amount to the University.

Despite also demanding financial recompense, Watkins said, “The primary goal of the Soh family is to implement change necessary to prevent this type of tragedy from occurring again. As part of that demand…there was a demand that the University demonstrate accountability in a meaningful fashion.”