A serial killer who preyed on prostitutes and drug-addicted women in San José was sentenced Wednesday to 110 years in prison. Adrián Arroyo Gutiérrez was convicted of killing six women and raping two. One of the rape victims got away and helped investigators identify Arroyo.

The 40-year-old Arroyo accepted the charges in an abbreviated procedure and will soon be transferred from San Sebastián preventive prison, where he has been since his arrest one year ago, to another, as yet undisclosed prison. He will serve no more than 50 years behind bars, the maximum prison length in Costa Rica.

Between April and September of 2015, Arroyo stalked down-and-out women in impoverished San José neighborhoods in San Sebastián and Hatillo and in Arroyo’s home neighborhood of Barrio México.

Though the court convicted Arroyo of six murders, investigators initially linked him to nine murders. Judicial Investigation Police (OIJ) had difficulty extracting DNA evidence from some of the bodies because they were in an advanced state of decomposition by the time they were discovered.

A key witness in the case said she was raped by Arroyo in November 2014. She testified that she had seen Arroyo with three other women who were later found dead.

Arroyo would solicit sex from his victims in exchange for drugs before strangling them to death and leaving them in abandoned lots, the court found. He is believed to be the second most prolific serial killer in Costa Rican history behind the infamous El Psicópata, who is suspected of being responsible for 19 murders in and around San José over a 10-year span.

El Psicópata was never caught.