Islamabad - A Pakistani university professor who went missing earlier this month has returned home safely, police and a family member said on Saturday.Senior Islamabad police officer Ashraf Shah said that Salman Haider was home, on the outskirts of the capital, Islamabad and that he is safe and well. Haider and three other rights activists who ran social media accounts known for their liberal views went missing earlier this month.Dr Haider Ashraf, the Lahore police chief, said all four missing men were at an Islamabad police facility, but would not elaborate on their circumstances. Shah said Haider has not yet given a statement to police about his disappearance. Haider's brother Zeeshan also confirmed his elder brother's return, but would not give any further details.Haider disappeared on January 6 and his wife received a text message from his phone telling her to collect his car from a roadside on the outskirts of Islamabad. Waqas Goraya and Asim Saeed went missing from the eastern city of Lahore on January 4, while Ahmed Raza Naseer disappeared three days later from the town of Nankana Saheb near Lahore.Haider, a poet, has been publicly critical of the Taliban and of the government's efforts to combat the militants. He had also participated in rallies protesting the disappearance of several activists from the separatist movement in Pakistan's southwestern Baluchistan province. The fate of many of these missing persons remains unknown.