Police arrested three suspects early Thursday as part of a probe into the Istanbul building collapse.
Project head Suzan Cayir, construction technician Ugur Misirlioglu and safety technician Arzu Keles Boran were arrested, said police sources, speaking on condition of anonymity due to restrictions on speaking to the media.
The seven-story building in Kartal district collapsed last week for reasons as yet unknown.
Twenty-one people lost their lives in the incident and 14 people were rescued from the debris.
Reporting by Filiz Kinik, Ali Cevahir Akturk:Can Erozden