Costa Rica’s Judicial Investigative Police (OIJ) identified the German man stopped Thursday morning while driving with his deceased girlfriend in the passenger seat of his car as 57-year-old Karl Alwanmeyer, and confirmed that the man is being held on suspicion of homicide.

During a brief press conference on Thursday, the OIJ also identified the victim as 51-year-old Mariana Esquivel Alfaro.

Alwanmeyer was stopped by police officers shortly before 3 a.m. Thursday morning in the neighborhood of La Virgen, in Sarapiqui, after residents called authorities to report a suspicious vehicle driving aimlessly around the neighborhood with a flat tire.

When officers stopped Alwanmeyer’s vehicle, they discovered the dead woman in the passenger seat. According to initial reports, Alwanmeyer was apparently trying to find a suitable place to bury the deceased woman.

Initial reports indicated that Alwanmeyer admitted at the scene that he had beat the woman to death; however, OIJ director, Walter Espinoza said at the press conference that the woman had no visible injuries and that an autopsy would be performed to determined the cause of death.

Sources close to the investigation but who were unauthorized to speak on the matter said that the woman is believed to have been asphyxiated.

The OIJ director said that Alwanmeyer remains in custody on suspicion of homicide.

According to the OIJ director, the victim was originally from Heredia and had been living with Alwanmeyer for about four months. However, the German man appears to be legally married to a different Costa Rican woman in the National Registry.

Immigration records show that Alwanmeyer has traveled frequently to and from Germany in recent years.