Sujith Mangala de Silva went to the police headquarters in Colombo this morning (June 15) and handed over the letter, through his lawyer Lilan Amarakoon.
His letter claims that two unidentified men in two motorcycles had visited his Katubedda home around 1.00 pm on June 12 when he was away, threatened his mother and made inquiries about him.
The journalist says he is making the complaint as he fears the lives of his family members and that of his own can be in danger from these persons.
Mr. de Silva is the president of the United Media Forum, a media rights group.
A few weeks ago, his senior colleague C.J. Amaratunga complained to the IGP that persons claiming to be from the CID had gone to his Anuradhapura home and made inquiries about him.