With four secular bloggers being killed by suspected Islamists in Bangladesh in recent months, police here have asked secular writers not to "cross the limit" and write anything which hurts religious beliefs of others.



"Do not cross the limit. Do not hurt anyone's religious belief," Inspector General of Police AKM Shahidul Hoque said as investigators struggled to nab the killers of secular blogger Niloy Chakrabarty Neel who was hacked to death at his flat here on Friday.



The "freethinkers" should keep in mind that hurting someone's religious sentiment is a criminal offence, Bdnews quoted Hoque as saying.



On the killing of blogger Neel, he said police were investigating it "with top priority".



He is the fourth blogger to have been killed since February this year. Hours after the gruesome attack, Ansar-Al -Islam, the Bangladesh chapter of al-Qaeda in the Indian subcontinent, claimed responsibility for killing 40-year-old Neel but police said involvement of the banned outfit cannot be confirmed yet.



Apart from Neel, other bloggers killed this year are Avijit Roy, Washiqur Rahman and Ananta Bijoy Das.



Meanwhile, a team of the Federal Bureau of Investigation (FBI) of the US met local detectives in Dhaka to share their technical expertise in investigating such cases, Deputy Commissioner (Detective Branch) Mahbub Alam of Dhaka Metropolitan Police told reporters after the meeting.



Alams said they also talked about the progress of investigation into the murder of secular writer Avijit Roy, a naturalised US citizen.



Police had primarily ascertained that the email claiming responsibility for Niloy's murder was sent from inside Bangladesh, Mahbub said.