Police have arrested a third suspect in the murder of a Kazakh diplomat at his house in Sector F-6/4 on Wednesday. Ahsan Saddiq, a superintendent of police for investigation, said the third suspect, Muhammad Hussain, was from Kazakhstan and was arrested in the NWFP. He said police had arrested two Chinese suspects, Hassan and Muhammad Ibrahim, in Islamabad earlier. He said police were also on the trail of a fourth suspect and would arrest him soon.