A new Human Rights Watch report 'documents extensive violations by Hamas security services, including warrantless arrests, failure to inform families promptly of detainees' whereabouts, and subjecting detainees to torture'. The posting here, on the HRW website, goes into further detail. One such detail:
Hamas's rival in the West Bank, the Fatah-dominated Palestinian Authority, arrests and detains Palestinians arbitrarily, including Hamas members or sympathizers, and similarly subjects detainees to torture and abuse. The intra-Palestinian political rivalry remains a significant factor behind many Hamas abuses against detainees in Gaza, Human Rights Watch found.
It's what's known as a symmetrical relation.