Investigators say Marcum, who was killed at her Bethesda home in October, died from a combination of asphyxiation and blunt force trauma.
Captain David Gillespie would not detail either the relationship between Landeros and Marcum or a possible motive in her killing. He did say "she was known to him and that at some point we've been told that he use to teach her Spanish."
A report from the Washington Post notes that Marcum and Landeros were acquainted through a mutual interest in yoga. Landeros had worked as a yoga instructor in the D.C. area.
Police believe the Landeros is in Mexico, and Gillespie says he thinks Mexico will be cooperative in the arrest and extradition of the suspect.
Landeros, 41, was born in Juarez, Mexico, according to the Interpol warrant for his arrest.
David Hawkings, political columnist at Hawkings Here for Roll Call, talks about the latest behind a Virginia lawmaker's push to get a high-skill immigration bill in the House.