He was a Mexican-born businessman and poet who gave Spanish lessons. She was a popular accounting professor at American University.

They met about six years ago and discovered a shared interest in yoga.

Last fall, Sue Ann Marcum, 52, was found dead, bludgeoned and asphyxiated in her Bethesda home. And police now have a warrant charging Jorge Rueda Landeros with murder.

Police think Landeros, 41, is in Mexico, where he has been writing acquaintances in the Washington area, saying that he has done nothing wrong.

“My soul does not bear the scar of any misconduct,” he wrote in an online letter, according to sources with knowledge of the case.

Sue Ann Marcum was was a popular accounting professor at American University. (Courtesy of American University)

A native of Juarez, Landeros spent much of the past 10 years living in the Washington area, according to Interpol and online residency records. He speaks English and Spanish, and Interpol lists his nationality as both American and Mexican.

Montgomery County police think that Landeros was a yoga instructor in the D.C. area, New York and elsewhere, and they’ve identified a collection of his poetry and a book he has written. Business records indicate that he worked as a stockbroker.

Marcum’s death, which became a high-profile case in the Washington area, was first thought to be a random killing. It shocked many in and around her neighborhood along Massachusetts Avenue, about two miles northwest of the District and just east of Glen Echo.

At American University, students and colleagues mourned the death of a teacher known to take an active interest in students, inside and outside the classroom.

Detectives knew about Landeros early in the case, said Capt. David Gillespie, commander of the force’s major-crimes division. But they had reason to focus on someone else: Deandrew Hamlin, 18, who was found driving Marcum’s stolen Jeep 13 hours after she was found Oct. 25.

Hamlin led police on a chase, crashed the Jeep and gave inconsistent explanations of how he ended up behind the wheel of the vehicle, according to court records.

But investigators could not put Hamlin inside Marcum’s home, and he was not charged with the killing. Hamlin’s attorney has long maintained that his client did not kill Marcum.

Police have found no indication that Landeros and Hamlin worked together, and they think that Hamlin might have found the Jeep after it had been moved from Marcum’s home, according to law enforcement sources.

Gillespie would not detail either the relationship between Landeros and Marcum or a possible motive in her killing. Neither would law enforcement sources, who discussed the case on the condition of anonymity because they were not authorized to do so.

The arrest warrant is not considered public in Maryland until Landeros is served.

In Mexico, Landeros presents himself as a man who has nothing to fear, according to sources.

“Krishna and Jesus Christ, my two most cherished teachers, would be able to hold me in their gaze and see me as nothing more than another reincarnation of their eternal message,” he wrote in his letter, according to police sources. “I will write later. This drama unfolds with the inevitability of a good Greek drama. Let us all enjoy our popcorn.”

The crime scene in Marcum’s home looked like a burglary gone awry. A window screen was cut, and items were missing. Detectives examined a rash of nighttime burglaries in the area as part of their investigation, Gillespie said, but could not link them to Marcum’s killing.

Police have collected a series of online writings from Landeros.

In a tribute to a yoga legend in New York, police say, Landeros wrote: “Here was a man who had labored quietly in the corner like Homer’s faithful Penelope, and not cheap with time, had taken four decades to peel off the many layers of his ego so that he could stand naked, luminescent, effulgent, nothing in him but the frame of a door through which walked in none other than Divinity.”

In one recent writing to acquaintances, according to police, he signals that he is aware of the police investigation and discusses its effects.

“Luckily, language is not yet a fugitive,” he wrote, “if indeed that is what I am now being considered by the local authorities of Maryland, and now by the globalized order authorities all over the world.. . . Language, the love of my life, will here be the vessel of my thoughts concerning the actions of those authorities currently mounting a campaign to apprehend me.”

“First and foremost,” Landeros wrote, “it must be made clear: I am an innocent man.”

Staff researcher Jennifer Jenkins contributed to this report.