Police recovered the throat-slit bodies of two underage siblings from a roof-top flat in Uttar Bashabo area on Friday night.The deceased are Mashrafi Ibne Mahbub and Humayra Binte Mahbub. Both are the children of Md. Mahbub who is working at Dhaka Wasa.Police primarily suspected the two were killed by their mother Tanzina Rahman, 28, who is said to be mentally unstable.Sub Inspector of Sabujbag Police Station Nowser told Jagonews24.com that, being informed we rushed to the spot.The dead bodies were sent to Dhaka Medical College Hospital morgue, he added.