The Palestinian Authority preventive security service released a Nablus official from custody on Thursday, after detaining him for three days, a Ma'an correspondent said. Nablus mayor Adli Yaish said Ayman al-Rabba, the municipality’s engineer in charge of issuing construction licenses, was arrested by PA forces on Monday. PA security officials said al-Rabba was under interrogation. They declined to elaborate. Al-Rabba was released after questioning with no criminal charges being brought against him, a Ma'an correspondent said. The preventative security service is ordinarily tasked with investigating suspected breaches of national security. In Nablus, as well as neighboring Jenin, Palestinian security services are going through an internal purge as officials vow to weed out corruption in their ranks. A number of security force members have been dismissed and administrative procedures have been taken against corrupt security officials, governor of Jenin Jibrin al-Bakri said Sunday.