Donald Williamson has patiently waited more than a decade for justice in the alleged slaying of his friend and former colleague — American University professor Sue Ann Marcum.

It’s been nearly 15 years since Montgomery County Police found the 52-year-old accounting professor beaten and asphyxiated in her Bethesda home. The popular instructor, who was admired by coworkers and students alike, was allegedly snuffed out by a person she trusted and had known for years.

That friend has been identified by authorities as Jorge Rueda Landeros. Investigators in the case discovered that he would be the sole beneficiary of a $500,000 life insurance policy were Marcum to die.

“I never thought they’d catch up with him,” said Williamson, a professor emeritus at American University who taught Marcum as a graduate student in 1985 and then later hired her into the accounting department. “I am proud that the police and the [district attorney’s] office didn’t give up. She … got murdered by an evil person.”

Rueda Landeros, 55, was extradited back to the U.S. from Mexico in 2023.

Authorities linked him to the slaying through DNA allegedly discovered under Marcum’s fingernails and on a weapon discovered at the home, according to court records.

Rueda Landeros is scheduled to be tried for first-degree murder on Oct. 20.

Questions still unanswered

While police and prosecutors say they have their suspect, many unknowns remain, including the nature of the personal and business relationships between Marcum and Rueda Landeros, and whether he collected on the insurance policy. These details may come out in the trial.

In addition to the life insurance policy, they shared an investment account worth more than $100 million. Marcum was stressed about how Rueda Landeros was handling the funds, according to court records.

Rueda Landeros’ attorneys with the public defender’s office could not be reached for comment and Marcum’s brother declined to talk to The Banner. The State’s Attorney’s Office also declined, citing the upcoming trial.

Though details about Marcum’s personal relationship with Landeros are sparse, she clearly enjoyed close ties with her students and colleagues at American University. A 2010 tribute video produced by the university recounted how hard Marcum’s death hit the school.

“She often had birthday parties at her home, and instead of asking her friends to bring her gifts, she’d ask them to make contributions towards the scholarship fund,” Professor Emily Lindsay said in the video, referring to a department fund.

Then-college student Einar Bar Shira recalled in the video Marcum’s penchant for mechanical pencils and her unbridled enthusiasm for accounting.

“I always thought that, you know, an accountant was just a person that was pretty serious and nerdy,” she said. “She was so different. So, I just wanted to be like her. Like, wow, this is so cool.”

Marcum, according to her obituary, was named professor of the year at the Kogod School of Business three consecutive times, and directed her department’s master’s degree program.

A scholarship supporting university alumni who want to pursue a master’s in accounting at its Kogod School of Business has been named for her, according to the university.

Less is known about her life outside the university, though much is known about how she died.

A chaotic scene

Details about Marcum’s death began unfolding from the scene of the crime — her house.

On Oct. 25, 2010, police responded to her Bethesda home on Massachusetts Avenue, according to an April 2011 first-degree murder arrest warrant sought against Rueda Landeros.

They discovered a chaotic scene inside. It appeared the house was ransacked, court records said. Some items had been stolen — the report does not specify what was taken.

Police concluded the death was suspicious, in part because a rear window showed signs of being forced open, the charging document said.

“The scene revealed that Marcum fought with — and quite possibly knew — her assailant,” court records said.

Forensic testing from the scene and from Marcum’s body recovered DNA that was not Marcum’s.

An investigation revealed Marcum had met Rueda Landeros between 2005 and 2006. Court documents elaborated on their financial interactions but not on the nature of their personal relationship: She made an initial contribution to the investment fund in 2008, and a 1099 form from that year, in Marcum’s name, lists its proceeds as more than $100 million.

“Investigators, knowing that Marcum was a University Professor, believed this to be very unusual,” court records said.

They accessed her computer and read emails between her and Rueda Landeros.

“It was clear,” court records continue, “in the more recent communications that Marcum was increasingly concerned and uneasy about the way Landeros was handling and spending the monies that had been in this brokerage account.”

‘Don’t give him any money’

Months after Marcum’s death, Rueda Landeros was regularly crossing the border between Juarez, Mexico, and El Paso, Texas, police said. El Paso detectives met with Rueda Landeros and obtained his DNA through a buccal sample —a cheek swab — court records said.

His DNA matched that found at the scene of the crime and on Marcum’s body.

“Landeros’ buccal sample identified him as the source of several of the unknown DNA profiles obtained from Marcum and items within her residence, to include what is believed to be the weapon used to strike Marcum and the scrapings from under Marcum’s fingernails,” court records said.

In late 2022, FBI personnel in the Baltimore field office received a tip: Rueda Landeros was likely living in Guadalajara and working as a yoga instructor under the alias Leon Ferrara, police said.

Williamson said that he isn’t sure about how close Marcum and Rueda Landeros were outside of their business dealings. Marcum had asked Williamson’s wife if she thought Rueda Landeros was serious about her. Rueda Landeros also wrote Marcum poetry, Williamson said.

Williamson added that he met Rueda Landeros just once.

Marcum had asked that Williamson advise Rueda Landeros on his taxes because he had not filed income taxes for several years.

The impression he Ruedas Landeros left, Williamson said, was not a good one. He said he warned Marcum about continuing the friendship.

“Don’t give him any money,” Williamson recalled telling Marcum. “Whatever you do, don’t give him any money. I couldn’t get her to drop him.”

A helper

Williamson recalled a happier memory from after Marcum had been hired and he was chair of the accounting department.

They organized an event for students to promote the department. They made brochures, purchased beverages from the department budget and secured a room for the event.

Williamson expected about 30 students to attend, but only two showed up.

Williamson considered the event a “waste of time,” but Marcum changed his way of thinking.

“Well, Don,” she told him. “We helped two people.”

Williamson said the moment personified Marcum.

He relayed that message when he eulogized her in front of about 1,000 mourners during a memorial service shortly after her death.

“She helped two people every day, every day of her life. That’s what Sue Marcum was all about.”